We introduced the Add-on Guidelines a few months ago, setting a common bar all add-ons need to pass, regardless of whether they are hosted on AMO or not. We also promised a more permanent location for them, which is now set up at MDN: Add-on Guidelines.
This doesn’t change their enforcement in any way. These guidelines have been in effect since we announced them, and the modifications they’ve had since have been very minor. Also, the document is currently awaiting editorial review, which means they’ll go through some readability improvements in the future. Any major changes to the guidelines will be announced on this blog.
The document explains how to get in touch with us if you want to report a violation. Millions of add-on users will have their online experiences improved with your help.