When opening the Add-ons Manager in either Thunderbird or Firefox, a user should be able to see at a glance which version of each add-on is installed -- without having to click on each add-on separately and scrolling down to see its version number.
Many years ago, there was a Firefox extension called MR Tech Local Install that would do this for Firefox, but I cannot recall whether or not it worked on Thunderbird. Once the MR Tech extension was installed, the Add-ons Manager main window neatly listed each add-on with its version number next to it. No clicking was necessary to find the version number of each add-on. Having that feature built into the current Add-ons Manager for Firefox and Thunderbird would be extremely convenient. It would save a lot of time, clicks, scrolling, and frustration.