[stumped]

i see the non clickable word Format, not formats, maybe I have some long forgotten customisation in place. please see my previous picture attachment
if i click where I see epub,original_epub I only get copy all - I could not capture an image with right click active.
oh & if I hover over that , the popup says see all books with format Epub,original_epub
I think we are on the same pane, comparing your pictures with mine, yet different results ?
and both blue Format words seem to be combined into a single link - I cannot right click only on one of them, successfully.
I tested also after deleting epub format from one book , so the only listed format was original_epub - sill all I got was copy all.
I am wondering if I once created a custom column called format, for some forgotten reason - probably to have it display in the main pane, and it is appearing in place of the default formats entry in the details pane.
if so, I am not sure how to track that down
yes , in build your own columns I have an entry called format, and a description of built from other columns...

UPDATE, all solved - I undid what I'd done long ago to book details pane, so that it shows what you guys see, - all good.
I guess the moral is to keep records of customisations !