Originally Posted by Perkin
Did/do earlier versions of calibre when converting change all the filenames to index_split_###.html.
If so then if there's a jacket.html and it contains the class="calibre??' tags I would of thought it would be same to assume it is a jacket that you want to remove rather than any commercial-jacket - which would have been renamed.
Does that make sense?
That is not foolproof.
Older (Arnold era) Baen books come with calibre## classed tags
all that signifies that Calibre was somewhere in the work flow
I rename many split... tags to a more meaningful (and short) name when touching up in Sigil, so it is quite possible (though rare) that all traces of a Calibre naming disappear.
The menu has: DB quality checks, Book quality checks, DB Tools, Book Tools. And as someone noted: rarely apply to all formats
Quality check = is something broken/mis-matched
Tools = Report, Fetch or Clean