Created attachment 874639 [details]
config settings (1)

Thunderbird 115.10.1-150200.8.157.1

I've needed to install MS Edge, as I have an NVR, embedded Linux, but
unfortunately Edge/IE "minded" - not usable with Firefox :(

Since Edge installed, Thunderbird opens all HTTP(S) links in emails with Edge,
which is for sure NOT what I want.

Tried this, as this is the newest relevant found:
https://www.lifewire.com/change-the-default-browser-in-thunderbird-2532751
network.protocol-handler.warn-external.http and
network.protocol-handler.warn-external.https
but DOESN'T WORK.

Thunderbird has all options (now) set to "ask everytime" or "ppen with
Firefox", but still opens Email links with Edge.

I've also asked here: https://support.mozilla.org/de/questions/1443387 a month
ago, no answer. 

So maybe a distribution specific issue?