OK, so:

- almost every keypress is saved (+ the size limit is in MBs), so there's no need to worry.

Having said that, this is really useful feedback - somehow it has never occurred to me that this is not obvious, which is silly. That's on me of course. Thanks!

I'll: - add a save shortcut (for forced save) with a visual cue (e.g. a toast saying "saved") - add better copy + another way of marking occasional save points

If you have more suggestions, shout.