Drop webext-https-everywhere
It's been sunset since January 2023.
See the following quotes and links
- https://www.eff.org/https-everywhere/set-https-default-your-browser
- https://www.eff.org/deeplinks/2021/09/https-actually-everywhere
TL;DR seems to be (on Firefox): the same can now be done with the dom.security.https_only_mode config variable.