He is using some Cuttingmachine what can also you do it yourself if you can find (borrow) the same small machine.
When he uses inside edge of "Schaltbrett" where big hole for shifter is, as leading edge for machine and on other side frasing head they move than parallel and it can be 100% accurate. Of course one marks it before cutting on wood with some CD Pen to be sure not to miss.
He is doing it with hand no CNC, this tool had that part that leads and than cutting head that follows so it is easy to copy one switch hole to another place.
All man needs is a little practice

and to cut newer model is a little easier than old model because one must not additionally make switch holders at edges and hole is all the way of same depth.
Festool 1010 EBQ

I know been doing it few times on my 190e to put more switches (as I am SA freak) with small drill and small file it can be done perfectly but too much work involved I wish I had than this Festool back then

Also there is smaller tools available, that fits in hand, which are better for our use, this is too big as for cutting big wood like for tables and furniture...
(Look in ebay for Bosch Oberfräse)