This morning I saw a critical update to WordPress ... and wondered what had actually changed.
When you need to compare the installed version of Wordpress (or any program, really) with a different version in the official repository, Subversion can help, although it is not exactly obvious. Here is the incantation:
svn diff --old=. --new=http://core.svn.wordpress.org/tags/3.0.4
With subversion 1.5 or later, you can use the shortcut:
svn diff --old=. --new=^/tags/3.0.4
Or to compare the current version to the new main 'trunk' --
$ svn diff --old=. --new=^/trunk