Yes, it's for multiple character keystrokes (for example, escape sequences are at least two characters).  Within the keymap generation function the keystroke is represented by a handful of individual `Char`s, and an array seemed to be simplest to me at the time.

I could subsequently convert the array to a string if you'd prefer, but I don't think it makes anything simpler.  In general, functions shouldn't be checking (or even care) which keystroke was used to invoke them; the part that matters to them is just the number of repeats.