The messages are sorted by number. Similar messages that have adjacent
numbers are grouped together.

The format is as follows:
<num>: "Message" (severity/ies)
Translation
Fix
[notes]

Messages listed as starting with <off> will have "Offset <num>:" prepended to
them; <num> is the 0-based (that is, the action byte is byte 0) decimal
offset of the problem byte, or first byte of the problem bytes, if something
longer than a single byte is invalid.

41: "All <type> are <desc> bytes long." (Fatal/Warn 2)
42: "Length does not match <variable[s]> of <val[s]> ..." (Fatal/Warn 2)
This pseudosprite is too short (Fatal) or too long (Warn 2).
Add or remove data and/or change <variable> (if applicable).

43: "<off> Sanity checker requires <num> byte(s) ..." (Fatal)
The sanity checker attempted to read bytes that didn't exist.
Add the required bytes to the sprite.
This is somewhat of a cop-out on my part, so given a good replacement error
message and a sprite that causes it, I'll consider putting the better error
message in.

44: "Invalid feature byte." (Fatal/Error)
The feature byte of this sprite is not valid.
Change the feature byte to something between 00 and 0F.
Which features are valid depends on which action you are coding. See the
wiki for the meanings of the feature bytes.

45: "Invalid nument1 or random-/variational-type byte" (Fatal)
This action 2 has a type byte with no meaning.
Change the type byte to 80-86, 89, or 8A for var/random, or 00-7F
for standard.

46: "Invalid action byte." (Fatal)
This is not a valid action.
Fix the action byte.

47: "<off> Invalid property <prop>." (Fatal)
The byte at offset <off> appears to be a property byte, but is not a
known propery.
Fix this byte and/or check preceding properties for validity.

48: "Action 6 appears to be missing terminating FF." (Fatal)
The parser hit end-of-sprite before finding the expected FF terminating byte.
Ensure that the FF exists and that the preceding <param> <size> <offset>
triplets are all valid.

49: "Insufficient <type>. ..." (Error)
50: "Extra <type>. ..." (Error)
The number of <type> sprites (real/include) seen since the most recent
action 1/5/A/11/12 does not match the number declared by that 1/5/A/11/12.
Add/remove sprites and/or adjust the declaring action.
Note that "-1 * 1 00" is interpreted as a real sprite in action 1 blocks and
most action 5 blocks.

51: "<type> unexpected here." (Error)
There was no reason to expect a <type> sprite here; the immediately
preceding sprite was not an Action 1/5/A/11/12.
Remove the sprite, or add an action 1/5/A/11/12.
Note that "* 1 00" is interpreted as a real sprite in action 1 blocks and
most action 5 blocks.

52: "Feature byte does not match feature byte of preceding ..." (Error)
This standard action 2 declares a cargoID for a different feature than the
preceding Action 1.  **OR**
This override action 3 attempts to override for a feature other than the one
the preceding action 3 set sprites for.
Change one or both of the feature bytes so they agree.

53: "Rand02s require power-of-two sets to choose from." (Error)
This random action 2 has an invalid nrand value.
Set the nrand value to 02, 04, 08, 10, 20, 40, or 80.

55: "<id> is neither callback nor cargo ID." (Error)
This action 2/3 attempts to use an invalid ID.
If you are trying to declare a callback, ensure that the high bit is set.
Otherwise, ensure that you padded the ID with "00".

56: "<off> Sprite set <set> does not appear in the preceding ..." (Error)
This standard action 2 attempts to use sets that are not defined by the
preceding action 1.
Add sprites to the action 1 or choose a defined spriteset for the action 2.

57: "<off> Invalid cargo type: ..." (Error)
This action 3 declares a cargo-specific cargoID for a cargo-type that
does not exist. This may also mean that the cargo does not appear in the
cargo translation table.
Change the cargo type, remove the cargo type/cargoID pair, or add the cargo
to the cargo translation table.

58: "Action 2 declaring no <type> sprites." (Error)
This standard action 2 declares no sprites for loadstate/loadingstates/
numlotssets.
Although not strictly an error, this is asking for a divide-by-0 error.
Change the offending byte.

59: "Signals require 48, 112, or 240 (0x30, 0x70, or 0xF0) sprites." (Error)
60: "Expected <num> (0x<hex>) sprites for this type." (Error)
The numsprites declared by this action 5 does not agree with the feature for
which these sprites will be used.
Correct the sprite so numsprites and feature agree. Valid values for
numsprites are listed.

62: "<off> ID <id> has not been defined." (Error)
This action 2/3 attempts to use an undefined ID.

63: "Expected <num> more properties." (Error)
This Action 0 ended before all properties declared were found.
Add missing properties, or reduce the number of properties you are setting.

64: "Expected more data for prop <prop>. (<num> bytes at <offset>.)" (Fatal)
65: "Expected <num> more bytes for prop <prop>." (Error)
Property <prop> does not have enough data.
Add missing data.
The action 0 parser thought it should be able to read <num> bytes at <offset>
(or at the end of the sprite). This does not necessarily mean that just adding
enough bytes to make that possible will fix the sprite.

66: "Property data is missing terminating byte(s)." (Error)
This sprite contains a variable-lengthed data that requires terminating
byte(s), but they were not found.
Check the sprite for variable-lengthed data, and make sure the terminator
exists.

67: "Action <num> already found at sprite <num>." (Error)
This NFO file has two or more action 8/11s.
Remove one of the action 8/11s.

68: "An action 8 must precede action <act>." (Error)
No action 8 has been seen.
Add an action 8 before this sprite.
This error will only be issued once.
Note that not all action Ds require a preceding 8; this message will not be
issued on non-resource-management Ds.

69: "Invalid <type> version number."  (Error)
The version number listed in this sprite is out of range for the object it
encodes.
Correct the version number.

71: "Variable size <size> is invalid." (Fatal)
72: "Condition <cond> is invalid." (Error)
This Action 7 or 9 sets <size> or <cond> to invalid values.
See the wiki for valid values and meanings.

73: "Condition <cond> requires variable 88." (Error)
74: "Variable 88 requires a GRFid condition." (Error)
One of the five GRFid conditions was attempted on a variable other than 88,
or vice versa.
Change the condition and/or variable so they agree.

75: "Variable <var> reqires a bit-test condition." (Error)
A bit-test variable is paired with an non-bit-test condition.
Change the condition or the variable.

76: "Variable <var> is <len> byte(s) long." (Warn 2)
This variable/var-size pairing is invalid.
Change the variable or the variable size.

78: "<off> <real> was found where literal <exp> was expected." (Error)
The byte at <off> was expected to be <exp>.
Change the byte at <off>, and/or check the feature byte.

79: "Expected <num> more strings for this action 4." (Error)
This action 4 contains too few "00" bytes for the number of strings it
declares.
Check that the strings are terminated, add strings, and/or reduce num-ent.

80: "<off> Value of <xoff>/<yoff> must not exceed 10h." (Warn 3)
<xoff> or <yoff> was set to too high a value.
Reduce the offset.

81: "<off>TTD only defines sprites up to 4984 (1E 13)." (Error)
Access was attemted to a TTD sprite that TTD doesn't define.
Reduce the sprite number.

82: "Color translation mode 3 is undefined." (Error)
A color translation of 3 was requested, but only 0-2 are valid.
Change the color translation mode.

83: "Sprite <num> is not a color translation sprite." (Warn 1)
Color translation was requested, but a sprite that is not a color
translation sprite was specified.
Specify a color translation sprite or turn off color translation.

84: "No ground sprite was specified." (Error)
84: "No non-transparent sprite was specified." (Error)
This house/industry tile was specified with neither a groundsprite nor
non-transparent building sprite.
Specify a ground sprite or at least one non-transparent building sprite.

85: "No standard action 3 exists prior to this livery override..." (Error)
A livery override action 3 was the first action 3 seen in the file.
Correct this sprite, or add a standard action 3.
This message will only be issued once, even if multiple override 3s precede
the first standard 3.

86: "<off> Testing nonexistant variable <var>." (Error/Warn 1)
This variational action 2 or action 7 tests a variable that does not exist.
Change the feature, type, and/or variable.

87: "Action 6 attempts to modify data beyond the end of this sprite." (Error)
The action 6 preceding this message attempts to add data to the end of this
sprite.
Add padding to the end of this sprite, or fix the action 6.

88: "There is no following sprite for this Action 6 to modify." (Error)
An Action 6 is the last sprite in the file.
Remove the action 6 or add additional sprites to the file.

89: "Action 1/A/12 declaring no sets" (Warn 1)
90: "Action 1 declaring sets with no sprites" (Warn 1)
The values numsets or numsprites, respectively, are 0.
Remove the Action 1/A/12, or set numsets/numsprites to their correct value.

91: "<off> Set <set> contains no sprites" (Warn 1)
This action A/12 declares a set with no sprites.
Remove this spriteset, or set numsprites to a non-zero value.

92: "Action 0 setting no properties." (Warn 1)
93: "Action 0 setting properties for no IDs." (Warn 1)
The num-props or num-info bytes are 0.
Set the num-props and num-info bytes to non-zero values, or remove the
action 0.

94: "Redefining ID <id> not used since previous definition ..." (Warn 1)
<id> has not been used since its previous definition
Remove one definition, or add an Action 2/3 that references that ID between
the two definitions.

95: "For feature <feat> the following cargoIDs have not been used..." (Warn 1)
The following list of cargoIDs were defined but never used.
Remove the definition, or add an action 2/3 that references the CargoID

97: "Set <id> defined by the previous Action 1 ..." (Warn 1)
The previous Action 1 declared graphics that have not yet been referenced
by an Action 2.
Remove the unreferenced graphics or add an Action 2 that references them.

98: "Variation <var> cannot be reached." (Warn 1/4)
Variation <var> has minval>maxval, or is completely obscured by earlier
variations.
Remove this variation or change minval and/or maxval such that
minval<=maxval.
This warning is level 4 on the first variation (<var> = 1) and level 1 on all
others. See also message 169.

99: "<off> No more data was expected." (Warn 2)
Extraneous data was found.
Remove the extra bytes or increase <num-props>, <num-info>, or <num-ent>.

100: "Default ID appears earlier in sprite" (Warn 1/3)
The default CargoID for this variational action 2 or action 3 appears
multiple times.
Remove the earlier references to the default CargoID or change the default
CargoID.

101: "GRFIDs with a first byte of FF are reserved." (Warn 1)
This action 8 declares GRFID with a first byte of FF.
Change the GRFID.
GRFIDs with a first byte of FF (with the exception of FFFFFFFF) are reserved
for TTDPatch internal use, and must not be used by GRF files.

103: "<off> Shifting variable <var> past its length." (Warn 1/4)
<shift-num> is shifting this variable further than its defined length.
Reduce <shift-num> so defined data is being read.
All 80+x variables are defined to be 1 byte long, even if TTD considers that
location to contain a word or a double. Overshifting an 80+x is a level 4
warning.

104: "Action 6 does not make any changes." (Warn 1)
105: "<off> This section does not make any changes." (Warn 1)
This action 6, or a portion thereof, does not make any changes to the
following sprite.
Remove the action 6, or fix it and/or the offending subsection so it changes
the next sprite.

107: "Label <label> has not been goto'ed." (Warn 2)
This action 10 defines a label that can only be used for looping.

108: "Label <label> has not been goto'ed since previous ..." (Warn 1)
No action 7/9 has pointed at this label since its previous definition,
making this definition superfluous.
Remove one of the action 10s, or change one of the labels.

109: "<off> Property <prop> is previously defined at offset <off>." (Warn 2)
This action 0 sets the same property twice.
Remove one of the definitions.

111: "Random 2 declaring only one choice." (Warn 3)
112: "All random options have the same ID." (Warn 3)
This random action 2 is not random, as only once choice is available.
Add additional choices, change the existing ones, or remove the sprite.

113: "Var2 accesses only constant variables (1A & 1C)." (Warn 4)
This variational 2 only accesses variables 1A and 1C; the result is known in
the previous var2.
Check other variables or remove the sprite.

115: "No preceding action 1." (Error)
This standard action 2 attempts to return graphics, but there is no
preceding action 1.
Add an action 1 or change the results to callback results.

117: "<off> Invalid operation <op>." (Error)
The byte at <off> is not a valid operation code.
Change to a valid operation code.

118: "Sprite set contains more sprites than given feature can use." (Warn 1)
This action 1 defines more sprites per set than the feature will use.
Remove the extraneous sprites or change the feature.

119: "Sprite set contains an unusual number of sprites." (Warn 1)
This action 1 defines a vehicle spriteset with 5..7 sprites.
Fix the action 1 to declare 1..4 or 8 sprites.

121: "<off> GRF ID at previously deactivated at offset <off> (<ID>)" (Warn 1)
This action E deactivates the same GRF multiple times.
Remove one of the deactivations.

122: "Action E is not disabling any GRF files." (Warn 1)
This action E does nothing.
Remove the action E.

123: "Source parameter <num> is invalid." (Error)
Src1 or src2 (see <num>) is not a valid parameter.
Read a different parameter.

124: "Target parameter is invalid." (Error)
The target parameter is not writable.
Write to a writable parameter.

125: "Only one of src1 and src2 may be 0xFF." (Error)
Both src1 and src2 are FF.
Change one or both of src1 and src2, or change the operation to 00.

126: "<off> A name for <lang> was previously specified at ..." (Warn 2)
This action F has already specified a name for language <lang>.
Remove one of the definitions.

127: "No name for <lang> was specified." (Warn 1)
127: "No fallback string was specified." (Warn 1)
In version 6 format, this action F specifies no name for one of the five
standard languages.
In version 7 format, this action F specifies no name for language 7F.
Add the missing name(s).

128: "<off> Zero parts were specified." (Error)
This action specified either 0 parts or 0 texts for one of the parts.
Remove the part/action, or add parts in the appropriate location.

129: "<off> Only <num> random bits are available." (Error)
This action attempts to randomize on more bits than are available.
Reduce either the number of bits requested or the first bit.

130: "<off> <num> (hex) bits are required, but only ..." (Warn 1)
More options are available that the allocated bits can randomize between.
Reduce the probabilities or allocate more random bits.

131: "<off> A probability of 0 was specified for this part." (Warn 1)
This part has no probability.
Remove this part, or increase its probability.

132: "<off> Parameter <num> out of valid range for variable <var>." (Error)
60+x variable <var> does not accept parameters this large.
Reduce the parameter.

133: "<off> Building sprites may not be null." (Error)
This action 2 specifies no building sprite here.
Remove this sprite section, or set a building sprite.

134: "Unexpected end-of-sprite reading building sprite <num>." (Fatal)
The sprite ended before all specified building sprites were read.
Add data or reduce the number of specified building sprites.

135: "First building sprite attempts to share its bounding box ..." (Error)
The first building sprite does not specify a bounding box.
Change the first building sprite to specify a bounding box.

136: "<off> Action <num> references reserved GRFid." (Warn 1)
Action E attempts to disable a reserved GRFid (FF ?? ?? ??), or an action 11
attempts to import from a reserved GRFid.
Remove the offending GRFid.

140: "Attempting to manage too many IDs." (Warn 1)
This resource-management action D attempts to {reserve/mark/check/find} more
IDs than are available for the corresponding feature.
Request fewer IDs, or change the feature.

141: "ID <ID> is out of valid range (<range>)." (Error)
<ID> is out of range for the specified feature. The given range is valid.
Check the feature, ID, and (if applicable) numIDs bytes.

142: "<num-cid> must be 0 for this feature." (Warn 1)
Only features 0..4 can usefully use a non-zero num-cids.
Remove the extra cIDs.

143: "<off> Using unspecified control character <ch>." (Warn 3)
The given control code has no meaning.
Remove the meaningless control codes.

144: "<off> Control character <ch> should not be used in this string." (Warn 1)
This control character does not belong in this string.
Remove the control character.

145: "<off> Control character <ch> does not match <data> ..." (Warn 1)
146: "<off> Control character <ch> reads data from multiple ..." (Warn 1)
147: "<off> Insufficient stack data for control character <ch>." (Warn 1)
The stack information for this string does not match this control character.
Check your use of code 86, and make sure that you're using the appropriate
stack character.
There are currently 5 recognized types of data: byte, word, textID, date,
and dword.

148: "<off> There is insufficient stack data to shuffle the stack." (Warn 1)
The control character 0x86 was found, but the stack does not have the
required 8 bytes of data.
Remove the 0x86.
For messages 143..148, <off> reports the *last* byte of a multi-byte
sequence, not the first.

149: "No terminating null found." (Warn 1)
This string does not appear to have a terminating null.
Add a 00 to the end of the sprite.

150: "Invalid severity byte." (Error)
This action B has an invalid severity byte.
Set the severity to a value 00..03.

151: "Unrecognized bit set in language-id byte." (Warn 2/3)
In version 6 format, only one of bit 5 or 6 is set with out the low seven
bits being 7F
In both formats, bit 7 is set in an Action B or F.
Unset those two (action 4) or three (action B/F) bits, or set all of the low
seven bits.
When Warn 2, following messages may indicate lang&7F rather than the actual
value of the lang byte.

152: "Invalid message id." (Fatal)
The messageID specified in this action B is not recognized.
Use a messageID in 00..03.

153: "<off> <num> is not a GRF parameter." (Warn 1)
The specified parameter is above 7F.
Use a parameter in 00..7F.

154: "Cannot override graphics for this feature." (Error)
Livery overrides are not valid for this feature.
Remove the livery override or fix the feature byte.

155: "Condition 0B requires 4 byte(s)." (Warn 2)
You're using condition 0B without specifing four bytes.
Change the condition, or specify four bytes.

156: "Metadata invalid. <data> must not be smaller than ..." (Error)
157: "Metadata invalid. <data> must not be larger than ..." (Error)
The specified metadata in not in the range that can be stored in a GRF file.
Bring the metadata into range.

159: "Metadata invalid. compression must be one of ..." (Error/Warn 1)
The compression byte is does not have one of the four valid values.
Change the compression byte.
Error if you attempt to set the compression to FF, Warn 1 otherwise.

160: "Metadata invalid. Sprite size exceeds 64K." (Error)
This line specifies a real sprite of over 65535 pixels.
Reduce the size of the sprite, or split it into multiple parts.

161: "<off> Text ID <ID> is not a valid text ID." (Error)
The specified text ID is not valid.
Specify a valid textID.
In an action 4, if <off> specifies byte 3, then the ID (in bytes 4..5) is OK,
but <num-ent> is too large.

162: "<off> Text ID %x has not been defined." (Error)
The specified ID is either not a valid TTD ID, or a DCxx ID that has not been
defined.
Ensure that you are using a valid ID, and, if DCxx, move the definition before
this action 0.
DCxx IDs must be defined before they may be used in Action 0s.

163: "<off> Checking for var0C in the range [<min>,<max>]." (Warn 1)
A check of var 0C has <min> not equal to <max>.
Change one of <min> or <max> so they match.

164: "<off> <callback> is not a valid callback for this feature." (Warn 1)
The specified callback is not called for this feature.
Change the callback or remove this <ID> <min> <max> triple.

165: "<off> <font> is not a valid font." (Error)
This action 12 specifies a font that doesn't exist.
Correct the font byte.

166: "<off> Set <num> declares glyphs across a block-break." (Error)
This action 12 defines a set of glyphs that are in two or more 128-character
blocks.
Split this set into two or more smaller sets that do not span a block-break.

167: "<off> The name for language(s) <ID> has no terminating null." (Fatal)
168: "The name-part starting at <offset> has no terminating null." (Fatal)
The specified string does not have a terminating null.
Check for errant control characters and/or add a terminating null.

169: "Variation <num> is partially obscured." (Warn 1)
An earlier variation in this varaction includes at least one of this
variation's <min> or <max>.
Reduce the range of either this variation or the obscuring variation.
<num> is, like most other things, 0-based; the first variation (which can
never be obscured) is variation 0. If the earlier variations obscure this one
completely, message 98 is issued instead.

170: "Default result cannot be reached." (Warn 1)
Same meaning as message 98, but for the default.
Make one or more of the variations default instead.

171: "<off> var-adjust performs a divide-by-zero or modulo-zero ..." (Error)
The <divide> or <modulo> portion of this var-adjust is 0.
Change the <divide>/<modulo> or reduce the varadjust to shift-and.

172: "<off> A shift-and var-adjust would suffice here." (Warn 2)
The function of this <varadjust> could be duplicated with a shift-and
<varadjust>.
Use the powers of the shift-and-add-mod or shift-and-add-divide var-adjusts,
or use a shift-and adjustment instead.

173: "<off> shift may not have both high bits set." (Fatal)
The high two bits of this <shift> are both set.
Clear at least one of the high two bits.

174: "Using an undefined trigger." (Warn 1)
This random 2 uses a trigger that is not defined.
Clear the undefined trigger bits.

175: "Invalid UTF-8 sequence: Overlength representation." (Error)
176: "Invalid UTF-8 sequence: First byte not followed by ..." (Warn 2)
177: "Invalid UTF-8 sequence: Encodes a character beyond the BMP." (Error)
An invalid UTF-8 sequence was encountered.
Correct or remove the invalid UTF-8 sequence.
Invalid UTF-8 sequences are parsed as a string of bytes (175, 176) or
ignored (177). Note that "Unexpected continuation byte" is not present, to
accomodate the use of unencoded 80..BF as TTD characters.

179: "<off> Language <ID> is not defined." (Warn 2)
http://wiki.ttdpatch.net/tiki-index.php?page=Action4 does not specifiy a
language for this ID.
Edit the wiki page or use a defined language byte.

180: "<off> Including TextID <id>, which contains a 00 byte" (Warn 1)
The textID <id> contains a 00 byte.
If this is a Dx00 ID, change its ID. Otherwise, find a different text to
include, define your own in the D000 range, or make this the last string
defined by this action 4.
Including a TextID with a 00 byte causes that 00 byte to be parsed as an
end-of-string character.

182: "<off> Embedded null byte." (Warn 1)
The byte at <off> is 00, but is not the last byte in the string, or in
the last string in this action 4.
Find some way to change this.
See also 180.

183: "The following Action 7/9s jump past the end of this file:" (Warn 2)
An action 7 or 9 jumps past the end of this file.
Change the last byte of the referenced 7 or 9 to a 00.

185: "Action 4 declaring no strings." (Warn 1)
This action 4 has a num-ent of 00.
Remove the action 4, or increase num-ent.

187: "<off> Undefined extended format code <byte>." (Error)
An unrecognized 9A XX sequence was found.
Remove the 9A or correct the XX.

188: "<off> ID <num> is defined with feature <feat>." (Error)
This var/random 2 or 3 attempts to chain to an action 2 that does not have
the same feature byte.
Make the feature bytes match, or unchain the sprites.

189: "<off> ID <num> is defined with feature <feat>." (Warn 1)
This variational 2 attempts to call an action 2 procedure that does not have
the same feature byte.
Make the feature bytes match, or remove the call.
This is not a bug in the NFO as such, but NFORenum will check the procedure's
variables against the procedure's feature byte, not the caller's feature
byte, which may conceal problems with the procedure, and/or reveal "problems"
that aren't problems.

190: "Autocorrector seems to be stuck in an infinite loop." (Fatal)
The autocorrector's rules are telling it contradictory things, resulting in
repeated corrections to the same byte.
Manually correct the offending byte, or do not use the autocorrector.
If this message appears, it should be considered a bug in NFORenum; please
report it as such.

191: "<off> <parts> field <num> reuses the following bits ..." (Warn 1)
This action F uses some bits multiple times.
Change one of the <parts> sections to use different bits.
<num> is zero-based; the first <parts> is 0, the second is 1, and so forth.

193: "Action 13 can only define texts in the C4xx, C5xx, C9xx ..." (Error)
This action 13 attempts to define texts outside its valid range.
Use action 4 or correct the textID.

194: "Anding with 0" (Warn 1)
This varaction 2 has a <and> byte/word/dword of 0, making the associated
<var>/<varadjust> pair somewhat useless.
Remove the pair, or adjust the <and> byte to an appropriate value.
This warning is not issued for variable 7E, on the assumption that you will
be using 1C to get the result instead.
This is message is based on the same theory as #202.

195: "Action 3 may not be both generic and an override." (Error)
This action 3 has a <num-ids> of 80.
Change the <num-ids>, or remove the action 3.

196: "Action F may not chain to itself." (Error)
Although action 2s may refer to their own ID, Action Fs may not.
Pick a different ID for either this action F, or the referenced action F.

197: "add-in-<num> should not be negative." (Warn 1)
This industry production callback has an add-in set to a negative value.
Set the add-in to 0 if you want no effect.

199: "<off> ID <id> previously specified at offset <off>." (Warn 1)
199: "<off> Cargo <id> previously specified at offset <off>." (Warn 1)
The specified cargo or ID appears twice in this action 3.
Remove the extraneous appearance(s).

200: "Prop 08 has not been set for ID %2x." (Error)
1) For several features, property 08 must be set before an Action 3 will have
any effect. This is one of those features.
2) Some features reference objects of a different feature. The referenced
object(s) must be defined before they can be referenced.
Move the action 0 for the specified ID to somewhere before this sprite, or add
an action 0 that sets prop 08.

201: "GRFID has a bit set that is clear in the mask." (Warn 1)
When testing for multiple IDs, the specified GRFID should already have had
the mask applied.
AND the GRFID with the mask and use that value for the GRFID instead.

202: "<off> Operation 0F follows a non-store operation." (Warn 1)
The operation preceding this operation 0F was neither operation 0E or 10,
meaning that the calculated value was discarded without being stored.
Trim the unnecessary parts of the left-hand side, or remove the op 0F.
This is message is based on the same theory as #194.

203: "No persistent registers exist for this feature." (Error)
This variational attempts to use operation 10 (store to persistent register),
but it is for a feature/type pair that does not have persistent registers.
Use a global register (op 0E) or adjust the feature and/or type.

204: "Cargo translation table previously found at sprite <num>." (Warn 1)
NFO files should not have multiple translation tables. Remove the extra
tables.
Also, because NFORenum is a single-pass linter, changing the translation
table partway through the NFO may cause NFORenum to object to valid cargos,
or accept invalid ones.
To prevent this, place the translation table before all action 3s.

205: "Invalid random 2 subtype." (Error)
One of the reserved bits in <count> for a type 84 random is set.
Make sure that you did not set bits 4 or 5 (the low two bits of the high
nibble).

206: "Cannot set (extended-)byte IDs for feature <feat>." (Error)
Non-vehicle features do not accept byte-sized IDs.
Set an ID from the C4xx, C5xx, C9xx, D0xx, or DCxx ranges instead.

207: "Cannot check for usage of undefined IDs: ..." (Warn 1)
Your copy of 0.dat or 2v.dat is broken. Ask for a new one.

208: "<off> Declared length <len> does not match actual length <len>." (Error)
A field that is supposed to contain the remaining length of the current
property does not.
Replace the old value with the specified value.

209: "<off> Found byte <num> of a <num>-byte escape while ..." (Warn 2)
NFORenum is reading an atomic data block (such as <and> in a varaction2) that
does not consist of either (1) exactly one escape and no hex bytes, or
(2) only hex bytes.
If the byte indices (first and third numbers) match, but the lengths (second
and fourth) do not, the escape is probably the wrong width for the field
it is supposed to represent. Narrow or widen the escape as necessary. If
the byte indices do not match, then check the preceding code for validity.
If possible, add escapes so this check will trigger earlier.
Unlike every other offset in NFORenum, these are 1-based offsets, not 0-based.

219: "There was no Action 14 specifying the palette." (Warn 1)
NFORenum encountered an Action 8 with GRF version >= 7, but did not encounter
an Action14 specifying the palette used by the GRF.
Add an Action14 with "INFO"->"PALS" palette information before the Action 8.