There is indeed no doc, except for the source.
Usually the easiest way is to record a macro to get the codes, and then edit.
Even I do it that way, since despite working a lot with SynEdit, I can't remember them all.
If I already have a macro, I record into a 2nd (temporary) macro, and copy the command from there.
The list of PascalScript commands is documented:
https://wiki.freepascal.org/Editor_Macros_PascalScript
If you want to harvest the "ec..." list, the description of each is in the ide folder, something like *keycommand*.pas and the resourcestring unit...?
You will have to keep out an eye, for when new commands get added. Since the extension of the macro list is just a side effect, and will most likely be forgotten to be documented....
Maybe it be easier if the IDE shows a help window, with a generated list....
What may need to be documented is the exclusion list.
E.g. you can use "single step" (debug) as a macro. But it wont work as you like => well, it will once. But if you have 2 single step, the 2nd is ignored. It does not wait for the step to finish, and the 2nd is "virtually pressed" when the first still runs, so the debugger ignores it. (just like when you press F8 while the debugger already runs)
And also switching editors wont work....