Allegedly, on or about 6 February 2019, Patrick O'Callaghan sent:
It's a question of basic usability. When I want to type an "international" character, it would be nice to see how to do it without having to root around in keyboard files. Accents are easy as I use dead keys (áéíóúñ) but other things are harder, e.g. the Spanish upside-down question mark which I can never remember how to get. I'm frankly surprised that no-one seems to have brought this up before.
I went with using the compose key, because of the lack of information about which keys to use (as we're discussing - quick key show utility), and I can usually figure out ways to type the usual culprits with the compose key (because it picks on common typewriter symbols that look a bit close to the accents you want to add to another character).
e.g. hit compose c then comma produces ç hit compose ? then ? produces ¿
I'd seriously like to see a new style of keyboard which includes more punctuation marks (dashes, proper quotes, different spaces, etc) on dedicated keys.