Remove tagged coverart

I'm trying to find the info where tagged cover art is stored, and how to batch delete this. I seem to be able to delete a downloaded image with ALT-T, which is not what I want. But where do I find the info for linked covers? There's a Tag called Cover, which sometimes contains a 1. Is this what I need, and how would I delete it? Maybe run a format value or replace action that targets the field and replaces the 1 with nothing (haven't tried yet if I can leave the field empty). Thanks a lot.

edit: I know I accidentally tag-linked two cover arts. And want to check if there's more in my collection.

I am not quite sure what you want to do.
If you want to remove the embedded pictures, you can first of all filter for
%_covers% PRESENT
which shows you all the files with at least 1 embedded picture.
%_covers% IS 2
would filter for files that have 2 embedded pictures.
Fromt then onwards it would still be easier to select the files and remove the files with a mouse action, e.g. with the function of the picture frame context menu in the tag panel.
Modifications in the tag panel have to be saved with Ctrl-S.

Yes, I want to remove the embedded pictures, not the downloaded ones.
I know I accidentally embedded on two albums. I also want to check if there are more in my collection (my ex did most of the digitizing back then). Just want to have an as clean collection as possible.

Great. This helps.
So under artists starting with A there are 30 files with embedded pictures sigh

"...with the function of the picture frame context menu in the tag panel."

Do you mean I right-click on every song, chose extended tags and then click on the x next to the image? Just trying to do the right thing instead of adding more FUs to my collection.

You can delete the pictures in one go:
Load the files,
filter the files,
select all files
right-click on the picture frame in the tag-panel
select remove picture
Press Ctrl-S

BUT: It is usually much wiser to have the pictures embedded in the files instead of only in the file system. as then the tracks also show pictures if you copy them to another device like the mobile or a car stereo (well this could pose other problems but not the one of missing pictures altogether).
So my clear opinion would be: keep the embedded pictures and even further: embed also all those that you only downloaded and have only in a folder.

Got it. Thanks a lot.

I'll have to think of the best option for this. At the moment I would guess that 10% of all files have the images embedded. I generally don't put music on my phone but stream it from a cloud service. If I'm not in Europe then I don't have music. Simples. But your comment gave me something to think about. So thanks a lot.

edit: Major pain is that most of my music is very niche, and there's no choice of cover art. Some of the files available are 2MB. I don't want to increase the single file size too much as storage space is always a bit of an issue. I also don't want to edit a few thousand images and then embed them.

Did you know that there is an action to modify the cover size? This aims mainly at the dimensions, but perhaps a smaller picture also reduces the amout of storage needed.
See e.g. the help:
https://help.mp3tag.de/options_format.html#resize