From MozillaZine Knowledge Base

Good news: Bug 262626 is patched as of the 2005-04-03 TB build. [1] --Wintogreen 01:51, 4 Apr 2005 (PDT)

Missing article

Noticed that the article is no longer there. I do not know if it is referenced in more KB articles. --Dickvl 01:07, 28 September 2009 (UTC)

The last entry I found at the "Wayback machine" for the page is from June 20 2008:
I changed the link in the "External links" section to the above. Alice 11:36, 29 September 2009 (UTC)

Preferential extension link

I removed the Preferential extension link from the External Links section of the article. See this post in the Mozilla Support community discussions forum. The Preferential project is apparently abandoned since the last update was in 2006 according to Alice 09:44, 23 September 2014 (UTC)