I was helping an elderly friend who is legally blind, with their computer. He uses the windows magnifier to zoom in so he can read what's on the screen. When I opened Firefox the menu and tabs take up an entire half of the screen (not an exaggeration). This is due to the removal of the compact view. There was nothing I could do to fix this problem and make his menu and tabs not to be floating and massive. What this means is that his content view is now less than half of his screen size. This is not accessible for someone with sight issues. I went through a couple of guides and alternative settings to edit in the about:config It looks like the past settings have all been disabled from making changes to the Firefox UI, including trying to disable proton. Everywhere I look it says that Compact Mode is no longer supported and will eventually be removed from Firefox.

I have been a lifetime Firefox user and I changed those settings for myself after the display update a few months ago. I would have to switch browsers if there was no fix. But for my friend who is legally blind I would be required to talk to an accessibility lawyer and see what my options are. Alienating people with disabilities because someone thought the extra space looks cool is unacceptable!