I often find that a Firefox extension I want to download from AMO (addons.mozilla.org) has been tagge as "incomaptible" and greyed out; the grey button often can't be right clicked to download anyway. It didn't use to be that way, and I'm not sure how which way to work around it neatly.
Please note this isn't the same as addon compatibility in Firefox, which is controlled by a config setting. This is about the Mozilla addons website greying out extensions it thinks aren't what you need. I don't know if it uses User Agent but if it does, I don't want to tamper with it, as this is very widely used to ensure correct working on many websites.
Often you can be downloading on one browser or platform, for use on another and it's incredibly annoying if the website "helpfully" blocks it.
What workaround might help?