I was tinkering with the custom key repeat settings in 0x5f5c and 0x5f5d and I realized that they always seem to be expressed in 30ths of a second. Shouldn't this depend on whether or not the game has _update60(), or for games with custom loops, whether or not they've called _set_fps(60)?

I guess it's not a critical problem if it stays this way, it just seems like it ought to track the fps setting.

Not a bug, apparently. It's in the manual now:

        Custom delays (in frames @ 30fps) can be set by poking the following memory addresses:

        POKE(0x5F5C, DELAY) -- set the initial delay before repeating. 255 means never repeat.
        POKE(0x5F5D, DELAY) -- set the repeating delay.