Of particular technical interest is that, on devices where Dark Mode is "unsupported" (i.e., it's not even available in the Dev settings), Invert Screen is still there, but doesn't behave like it used to: it's no longer relying on hardware inversion, it's instead doing full-screen software inversion... I don't quite recall if that was the case earlier, but it also disables REAGL on devices where that's otherwise supported (which makes sense, as those waveform modes and processing passes are optimized for black-on-white text).
(This is probably a byproduct of technical limitations on the only device where Dark Mode is currently supported: the Elipsa, which doesn't support hardware inversion, but does support nightmode waveforms).
This is purely an interesting technical quirk. To make either of these modes actually bearable, having dedicated waveform modes is of much stronger importance than how the sausage gets made
. (Which is why it's unsupported and/or hidden away on every device that doesn't have those
).