Updated man page. Also added some non-documented parameters.

@VictorDenisov would it be OK to rename NO_LEADING_ZEROS_SERIAL to LEADING_ZEROS_SERIAL with true default value?

Yeah. Totally. I guess now the configuration will look like
LEADING_ZEROS_SERIAL off
?

Yes. Any of these statements will suppress leading zeros.

LEADING_ZEROS_SERIAL=off
LEADING_ZEROS_SERIAL=NO
LEADING_ZEROS_SERIAL=False

(the argument is case-insensitive, so no does the same thing too)

Code looks good and should catch all needed use cases. I think we should merge it in.

To drop keywords with negative logic (e.g. NO_BANDSWITCH_ARROWKEYS) it seems we need to document the default value of the boolean values in the man page.

It seems further desirable to have a command to show the state of the boolean controls in the running program.

But both may be later additions.

I'd keep legacy negative logic parameters. It would be more work to document such a change than the actual benefit. But at least for new configs we shall stick to positive logic.

Showing (and editing + reloading) configs is related to #233: one idea could be to move all globals and their initialization out of main into a data.c (like for the tests). But this is also more for the future.

I'd keep legacy negative logic parameters. It would be more work to document such a change than the actual benefit. But at least for new configs we shall stick to positive logic.

Showing (and editing + reloading) configs is related to #233: one idea could be to move all globals and their initialization out of main into a data.c (like for the tests). But this is also more for the future.

I agree to both. They are ideas for the long run.