Couldn't trigger it on M2 or 200D - don't know if it's supposed to work there
No, those are fully EOS models codebase-wise.
I posted this in the DIGIC 8 thread because this kind of scripting is expected to work on the mixed codebase models (mostly EOS with some Powershot legacy). Those are the newer Powershots (sx740, sx70, g5xII, g7xIII) and EOS M cameras (M50, M200, M6II). I'm sure about the M50 and sx740 (having seen their firmware), the rest is speculated. No idea about the other DIGIC 8 cameras.
If someone happens to have a firmware dump for any untested models, the presence of some strings ("extend.m", the keywords, etc) may indicate this feature.
I should note that only keywords and syntax are common between the PowerShot and EOS version of Canon Basic, most event procedures are different, the examples from that wiki will not work here.
As for the dump, thanks, but I already have all CHDK-supported fw dumps.
I did not mention it yet, but setting the camera bootflag(s) should also be possible from a script, without requiring an encrypted binary. Executing fw functions (named or not) is also possible.