I installed the development version on J4.2 Beta, and it all seems to work smoothly 🙂
What I miss (compared to J3) is the changelog info for each extension (in J3 available when hovering the version number).
Sometimes that info comes in handy when determining whether an extension can already be updated or not.
Thanks for testing. The changelog DOES show. But only for extensions that are not up to date yet. When updates are available it will show the available new version number. And you can hover over that version number.