Firefox Developer Edition - Setting a particular preference causes add-on installs to fail
I'm using Firefox Developer Edition v79, and I've been getting plagued by a particular issue for a while, but only recently found a bug report that clued me into the cause - and it's specific to the portable version only.
Preface:
Firefox prohibits extensions from working on their own site (specifically, addons.mozilla.org). In order to allow extensions to work on this protected site, you have to do the following in about:config: