TBExtInt allows users to install Thunderbird extensions from Firefox, skipping the need to save Thunderbird extension files first. This extension is for both Firefox and Thunderbird. But you don't need to install it into Thunderbird if you have ThunderBrowse installed already. Version 0.4 removed the requirement for ThunderBrowse to be installed, you can install this extension into both Firefox and Thunderbird (you will need to do this onto both unless ThunderBrowse is installed).
||Windows 95/98/Me/NT/2000/XP/Vista, Firefox 2.0 - 3.0.1