How to add a note to myself in bibliography?

Question

How can I add a comment to myself in a .bib file to be read by biber? I've checked out answers like this but they are about adding comments for readers to see, whereas I'm only looking to add these for personal documentation.

Answer 1

Anything in a .bib file that isn't part of an entry is a comment, so you can just type. Here are some examples of comments in a bib file.

This is a comment

Now here's an entry:
@BOOK{blah,
    ...
}

% You can also use markers, if you want, but they're unnecessary

If you need to comment out an entry, the @COMMENT can be useful

@COMMENT Even though this looks like an entry, it isn't @BOOK{blah,
...
}

Actually, btxdoc recommends just leaving off the @ like this:
BOOK{blah,
    This still is a comment even though it could look like any other entry
}