If you find a useful add-on at the Firefox Add-ons home page, you will find a green button that you simply click to install the extension. But sometimes, when an add-on is made by someone with his own web site they tend to store them on their servers, and offer the setup as regular XPI (extensions) or JAR (themes) files.
So what do you do when you find one of those two files and you want to install them?
There are two ways you can use:
- The first way, is to drag and drop the file/URL of the extension in the Add-ons manager (Tools>Add-ons). The normal installation window will show and you’ll be ready to install.
- The second way, is to modify a voice in the configuration page, to unhide a “secret” install button inside the Add-ons Manager:
Now you will have an Install button in the Add-ons Manager, that will enable you to browse your computer, and look for XPI and JAR files to easily install them.