Hi Pascal, the provider had proactively blocked my site. I did some research myself and found out that Joomla doesn’t have a core system plugin with that name. I deleted that plugin. Just so you know, I even found and deleted this metacache plugin on another site I manage.
Unfortunately, the HTProtect malware scan didn’t show anything. After I took action, the provider ran another scan on the site and found nothing.
I can take a look though, I guess the file might still be in a backup somewhere.
If I find it, I’ll post it here.
Cheers
Jochen