Default page templates still available after deletion

So, I initialized a new theme using the CLI and it featured a bunch of default pages...

I didn't need them most of them so I decided to delete most and rename the rest. Yet, the pages still persist after deletion of their Twig templates. - There are no blueprints for any pages in the user folder.

I found default.yaml, external.yaml and modular.yaml in system/blueprints/pages. Are these partly the culprits?

Pages like Error and Form continue to populate the Add Page modal in the admin panel without any apparent trace as to why or how.

I tried grepping for them with no luck.

Are these templates referenced somewhere or kept in cache or what? What do I need to do to remove them completely from Grav?

These templates comes from Error plugin and Form plugin.

You can hide these templates by going to admin plugin configuration in Plugins > Admin and hide these page types.

the files inside system/blueprints should be left untouched, and more generally, anything outside /user folder should be left as is.