Not sure what command-line options are available, or how to find out what they are.

If the read-me could include a link or some info that would be great.

Thanks!

Check documentation, whether the connection to bbotk is clear / has to made clear?

Some browsers don't have support yet (shame on them), so a message about that should be nice (not for the user, though).

There are often instructions preceding the actual tablature providing the reader with instructions, capo usage, etc.

There are also often lyrics associated with the tablature which are place appropriately with the corresponding notes, chords, etc. in the tablature itself.

The instrument's tablature itself is not dependent upon this content, so it should therefore be a configurable option.