[mzel]

After about 8 years of using KoReader, first on Kindle, then on Kobo, I finally managed to RTFM. It did provide useful information!
So I was annoyed with the rendering of some books, where the gap between the last line and the status bar was way too noticeable.
"Reclaim bar height from bottom margin" helped, but I still do not quite understand the logic. The way I read in the manual I should see the status bar overlap (at least partially) the last line when it is on. In my case I see a normal gap of about .3 line height. When it is off I see about 1.5 or almost 2 lines gap.
I understand the "Bottom Margin" and some font features affect this too. I have Bottom Margin at the default 15. I also notice this more with some fonts than with others