http://getfirebug.com/layout only mentions how to fix one's own web pages, but not how to fix viewing other peoples, e.g., http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=611955 One can disable the CSS item for that page, but not get firebug to remember that setting for that site, as there are no instructions as how to do that.

Firebug does not record settings for any site, as far as I know.

Holy moly. Better put that atop some FAQs. Tell them to try http://userstyles.org/ etc. instead.

Else they will tell people that Firebug is the right tool, http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=611955 instead of Stylish, etc.

The debian.org bugzilla entry is not under our control. Moreover there is nothing in that entry about re-applying site edits. I'm sorry if you misunderstood that post, but really you need to get the clarification from the folks who wrote it, not from us. We can't really start our FAQ with long list of things our tool does not do, even if you might have gotten the wrong impression from something you read.

Actually there is an entry in the FAQ: http://getfirebug.com/wiki/index.php/FAQ#Can_I_save_to_the_source_the_changes_I_made_to_the_webpage_I.27m_seeing.3F

Also please note, that there are several extensions to Firebug, that offer this functionality like FireFile and cssUpdater. See http://getfirebug.com/wiki/index.php/Firebug_Extensions.