https://blog.mozilla.org/addons/2020/03/10/support-for-extension-sideloading-has-ended/ The issue should have been present in Firefox 74 when the situation the "sideloading" of extensions was modified. Extension / Add-on developers may have to change the manner in which they provide Firefox extensions. Firefox 74-plus no longer searches the hard drive to look for those types of extensions; where previously Firefox would "see it" and automatically use it & display it in the Extensions Manager, which was changed to automatically disabling it at some Firefox version in the past. Now the "security" has been pushed up a notch, the user has to specifically install the extension via the XPI file method. One thing that still works is to "manually" install the extension '''XPI''' file once the user downloads & saves the XPI to their computer. Then while Firefox is open the user drags the XPI into the Firefox browser window to do a manual extension. That should work with Trusteer Rapport, BUT you need to find the XPI file to be able to proceed.

I just want Mozilla to fix it so that I get the option to enable Rapport, just like before.