Right now, there's no way to tell (short of looping over all event names) which events are bound to a keysym. To get "Select All" behaviour for Control-a, I have
event add <<SelectAll>> <Control-a> <Control-A>
in my app. What I didn't realise (as I develop on Windows) is that, on Linux, these keysyms are already added to <<LineStart>>. When someone reported that Control-a wasn't doing 'Select All', we had to guess and poke around to find what was happening. It would be helpful if
event info <Control-a>
which is currently invalid and returns an error would, instead, return a list of all events which have the keysym added.