My "apps and features" (in Settings) has a couple of 'NoUiEntryPoints' "apps". And the start screen - many more.
Is it safe to delete them? I know there is a question about how to remove them. I'm asking if it really is safe to do that without checking first what they are. (How can that even be done?)
Yes, it is safe to remove them. At one point these "apps" were generated whenever you used the Visual Studio Designer which used this approach to display the preview. This has been fixed since, but the "apps" will remain installed in your PC unless you uninstall them manually.