PrefBar users:

The following is a list of all PrefBar installation packages, I could still find on mirrors. They are sorted from newest to oldest. The ones with the "lock" in front of the file name are signed by Mozilla.

⚠ Please be aware, that PrefBar is no longer maintained! It is not recommend to install any of these versions!
They most probably don't work well with current versions of SeaMonkey and they won't install at all on Firefox 57 and above!

PrefBar's functionality has been replaced by a list of replacement Addons. You can find this list on the PrefBar migration list page.