It's possible to find many of AE's command IDs by running the following ES function and filling in whatever menu command you're after:

app.findMenuCommandId("Go To Keyframe Time");

But many other commands that aren't strictly "menu" commands seem inaccessible / hidden. For example, it seems impossible to find the commands for shifting keyframes left or right (represented in the hotkey editor by entries like "NudgeKeyframesEarlier" or "Shift Selected Keyframes 1 Frame Earlier").

It'd be great if you could expose these secret commands to scripting, by giving them entries in the function above, giving them command IDs, and/or by building an event listener panel that mirrors back the actions you're performing, in the form of command IDs / names, or some other scripting-friendly mirror of each command.