The goal for this extension is to be part of the (as-yet nonexistent) Web
Development extension, which will contain plenty of CSS and page information
goodies. In the meantime, enjoy.

For HTML validation support, you will need:
- OpenSP development libraries (libosp4 on Debian)
- (to compile) OpenSP development headers (libosp-dev on Debian)
- DTD's for the documents you want to validate
  (sgml-data and w3c-dtd-xhtml on Debian)

Everything needed for Link Checking is built into Mozilla. You may want to go
into about:config and increase network.http.max-connections and
network.http.max-connections-per-server for a speedup.