There were some modules that did not offer "or (at your option) any
later version" in their license and these had to be left alone.
This should solve the incorrect FSF address issue #4 on GitHub.
This command was used:
find . -type f -print0 | xargs -0 sed -i 's/return undef/return/g'
The idea behind this commit is described on http://oddmuse.org/wiki/Refactoring page.
In short: 'return undef' returns (undef) in list context (a list with one element),
which is wrong.
Replaced the $Id$ tags in $WikiDescription for all the modules and wiki.pl itself with a link to the source and an appropriate wiki page, if possible. This is shown in action=version and should help users figure out what another wiki has installed.