[photochemsyn]

On Firefox, you can just prepend "about:reader?url=" to any web page and you get the plain-text reader view. There's apparently a config setting in the userChrome.css file to make reader available like this on all sites.

[Poppys]

In Edge you can highlight text and click read in Immersive Reader or prefix the url with read://

Some sites have it in the address bar, but I've never found any documentation from MS that makes it clear how to ensure that it is always there.

[nkrisc]

That's a good point, and a good tip for when Firefox doesn't prompt it automatically. I'd forgotten entirely about reader mode on Desktop, I do use it all the time on mobile though.