Due to problems I had with Craft 3 Beta 23 I switched back to version Beta 22 (I did this a couple of times)
I do this by importing an sql dump of beta 22 and by directly requesting Beta 22 via composer.
The strange thing: Craft forgets about Plugins it had installed. They simply do not appear anymore in the plugins list, although they are installed via composer and nothing changed in them.
I cleared storage/runtime and I also cleared the DB cache via utilities, that does not help.
Any hints why Craft does not show the plugins anymore in the list? Is there another cache?