I'm using Drupal Core 9.4.8 and installed the latest version of "File Delete" with a patch that allows the file to be deleted immediately and to force delete. And physically deleting the file doesn't seem to affect its presence on the site.
Does mobile-friendly mean that the site detects what platform is being used and one of several views are used accordingly?
I'm joining a volunteer-team that maintains a Drupal-9 site that has had some criticism, that it looks old-fashioned and it doesn't look good on a mobile-phone. I'm going to have to learn Drupal and I'm working through an on-line Drupal 8 tutorial. The impression I'm getting is that it is similar to a strongly-typed Object-Oriented system with multiple geometric display-options on top of it, no doubt more experience will expand or correct that.