This is absolutely splendid. It has the hallmarks of a wonderful spoof video but is actually real.
Presumably UEFA have issued a notice to all officials that after the newly-introduced fifth officials have been receiving a lot of criticism for not doing an awful lot, they should really stress the point about their importance.
This guy has taken this to heart, doing a focussed warm up including specific stretches for the movement he will need to look for the ball. and it’s beautiful.