Librera: how to display 1. horizontal lines and 2. unicode

I love the Librera app and have all my ebooks in it now. I have encountered two wrinkles and I suspect the settings for both are in similar places; I just can’t find where that place might be:

  1. I can’t figure out how to make horizontal lines display when reading .epub files. I have confirmed they are there in other ereader apps. And Librera knows something is there because it displays the scene breaks marked with a horizontal line as an extra blank line.
  2. Certain unicode symbols, like :mushroom: and :ringer_planet:, show up just fine, and others don’t, like :bat:. Again, inferior ereader apps display all the ones I’ve tested without issue.

This doesn’t seem to be a function of the display font, nor of that “Night-mode enhancement for AMOLED displays” setting often cited as a source of problems.

These are pretty basic text elements, especially the horizontal line, so I’m sure I must be doing something wrong. Any ideas?