My browser is Pale Moon. Partly because I don’t want to be trapped in the Chrome tunnel, and partly because of the aesthetics.
Now I see:
Unfortunately, your browser is unsupported. Please switch to a supported browser to view rich content, log in and reply.
Our popular open-source graphics forum is not supporting a popular open-source not-google-owned browser? That would be sad.
Pale Moon is updated regularly to maintain compatibility and to try to avoid the go-to-chrome traps. I was behind: I have now updated to latest version. But no go.
I’ve been getting the same message in stable Firefox since February. I’ve turned off all extensions, but it does not help. It’s the same on macOS and Linux (Flatpak). I keep Chromium around to be able to use the Pixls.us forum.
I realize it’s probably some about:config tweak that messes things up, but I’ve done enough troubleshooting. Strange thing that no other website seems to dislike my Firefox config. It’s just a Discourse thing.