[01100001]

I wanted a bullet/unordered list so I could easily differentiate, at a glance, the different terms of a field (tags, or filenames (custom column))—which look like one long line of links by default.

In the end I decided that going the least intrusive way (albeit not best aesthetically or preferred) is better than hacking code in this manner unless absolutely necessary.

Just a bit of CSS code helps me with that (added under Preferences > Look & feel > Book details > Text styling):

/* CUSTOM */
#_filenames {
    color: red;
}
#_filenames .title {
    color: black;
}

So now, my Filenames (#filenames) field in Book details pane, looks like this:



Simple, yet much better (than default).

I know this isn't what I asked, and you all were very kind and helpful with my actual question. What learnt here, I am sure will be helpful elsewhere (and to someone else).

Thank you all!

Reference: https://doc.qt.io/qt-5/richtext-html-subset.html