Starting with Mozilla 1.8 beta2, the best way for applications, vendors, and extensions (if needed) to add to default preferences to add VendorProductTokens or VendorComments is to add a default preference of the form general.useragent.extra.identifier. All of the general.useragent.extra.* preferences will have their string values added to the User-Agent string in alphabetical order by identifier. For example:
pref("general.useragent.extra.megabrowser", "MegaCorpBrowser/1.0 (MegaCorp, Inc.)");
pref("general.useragent.extra.tinydistro", "TinyDistroLinux/2.3");
However, I've tried it and it doesn't work. Has it been removed?
Thanks.