Hmm, apparently Edge still supports Manivest v2: https://learn.microsoft.com/en-us/microsoft-edge/extensions/developer-guide/manifest-v3#manifest-timeline-for-microsoft-edge-and-partner-center

The text reads like it’s been AI-generated, so not sure if any of this information is worthwhile or up-to-date, but it seems to be the official source for this kind of information, so I would hope they’d update it, if anything changed…