Comment by gpm

So, I don't have any good ideas why. Can you give me more information about what exactly happens? Can't promise anything but details might help.

I.e. something like

- I open the browser console

- I click the .xpi link

- The following appears in the browser console immediately after clicking the link:

    WebExtensions: new intermediate certificate added api.js:15
    WebExtensions: signatures re-verified api.js:23

- My addons do not come back

- If I try to install an addon from addons.mozilla.org I get <this message about the addon signature verification failing> in the browser console.