I just upgraded from Matomo 3.14.1 to 4.0.0 (installed and updated via DirectAdmin and Installatron) and started getting various System Check warnings.

Settings	System Check	System Check / Informational

Attached:
matomo_system_check.txt

The issue about ExampleTheme seems like a bug, and is what I'm reporting. I'm not aware of having installed anything by that name and suspect it may've been something that went wrong in the packaging of the release or something?