Fix ISO verification using checksum
The tool we proposed to verify the Tails ISO on multiple platform is via a Firefox plugin. The background for that decision is that this way we can have a procedure that we can test ourselves, and be sure to work on Windows, Mac, and Linux as well. And we also make sure that users have downloaded those software through HTTPS. That's no magic wand, but it's better than nothing.
But the tool we proposed since the beginning, MD5 Reborned Hashed has stopped working in recent version Firefox. There was a workaround for some time but it also stopped working. So we're left with nothing for recent Firefox versions.
An alternative proposal is to switch to using Chrome instead of Firefox. Or document solutions for both Firefox and Chrome.