Hi all: I also bump into this. I confirm that I can reenable the webext-* installed extensions going to the preferences, disabling the extension and enabling the extension again. As Christoph already stated that works up to the next firefox restart.
I've also found that the extensions I installed from within firefox are working correctly as expected, unlike those installed from apt. I'm on Debian sid. Firefox is 80.0-1. Best regards, -- Rául Sánchez Siles
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