MnenhyIn Mozilla Application Suite and SeaMonkey 1.x, removing extensions is not as easy as it is in SeaMonkey 2.0, given that the latter uses Firefox-based infrastructure.
First off, there is Mnenhy, which has many modules and which is more geared towards expert users. The important module is the Chrome Manager, which is accessible from the Tools menu.
* For SeaMonkey 1.1.xx, I use Mnenhy 0.7.6.666 (Can't remember where I got the version with the .666 patchlevel, but this should be the one for SeaMonkey 1.1.xx);
* For Mozilla 1.7.13, I use Mnenhy 0.7.6
Mnenhy 0.7.6 is compatible with Mozilla 1.7 and SeaMonkey 1, and it can be downloaded from mnenhy.mozdev.org
Extension Uninstaller 0.2Unlike Mnenhy, this is one is more user friendly and even has easy-to-read error logs in case something doesn't work.
Extension Uninstaller 0.2 also requires the Extension Uninstaller API, which should be installed first.
Now, the problem with getting Extension Uninstaller is that its original website with
URLs is offline.
The only relatively good references I found to it are in
— where only the addons.mozilla.org extension pages are references, but these are unfortunately closed, too.
The solution is to peruse the original official URLs in the Web Archive.:
Snapshot from 2010-03-04
There, scroll down to the Install section, see the "Install For:" Mozilla link. Right-click on the link, choose "Save Link Target As..." command to save the XPI.
It's a bit more difficult With the Extension Uninstaller API .xpi, which can be separately had from archive.org.