Install an extension or theme Install

Install an extension or theme file you have downloaded and stored on your hard drive. Middle clicking the button will open the window to control which sites can install extensions.

Installing Extensions and particularly themes that you have downloaded can be quite a trick. This button makes the process simple and hassle free.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey
This button is a legacy add-on, and can not be ported to Firefox 57+.