Firefox 3 is great, but a few of my "required" extensions still haven't been updated for this yet-to-be-released version. One of which, Remove It Permanently, is essential for dealing with badly laid out websites.

Well it turns out that in that case, it's just a matter of:

1. unpacking the XPI file (it's a renamed ZIP file) and
2. bumping the "maxVersion" in the install.rdf file.

Update: Remove It Permanently 1.0.6.4 was released on 13 June 2008 and is compatible with Firefox 3.