The Innocraft Whitelabel plugin adds a "Widget.filterWidgets" hook callback called 'removeWidgets' which removes all widgets with setCategoryId('About Matomo').
Since a related change in Matomo 3.12.0 this will hide admin widgets like "System Summary" and "Tracking failures".
It would be great if the plugin had an option to disable this behavior.
@MichaelHeerklotz can you email our support shop at innocraft.com about this? That be great. Cheers