P: (Masking) Button to delete all hidden masks

Indeed it would be useful to have an icon to mark hidden masks, or masks that contain hidden components, in the Settings Window.

I recommend you to suggest the idea, I will vote for it.

As for the deletion of multiple masks/components the best and the simplest solution is to allow us to be able to select Multiple  components.

Deleting multiple, hiding multiple, etc...anything would become easier like that!

I will suggest this last one.

Footnote: it also occurs to me that it could be convenient to label masks that are hidden/inactive as such in the copy-settings window. That way one could easily accomplish the same result by copying all settings minus the inactive masks and then pasting to the image after resetting.

Ah, I was unaware of the right-click delete all - thanks!  By "extraneous", I simply mean masks that I'd inserted that seemed no longer useful for whatever reason. In some cases they had no adjustments (!) or I just no longer found them necessary.

A "Right Click : Delete all Hidden Masks" could do.

We already have "Right Click: Delete all Masks".

What do you mean with "extraneous masks" ?