McGregor can use his length well and punches well, but isn't a particularly hard hitter by boxing standards.
The only new thing I learned is that McGregor is surprisingly bad at generating power on the inside (normally he would throw an elbow in that scenario I guess?). Mayweather figured this out early on, which is why he stopped hanging out at range and started walking McGregor down. Without the distance to throw long punches, he didn't have enough pop to threaten Mayweather; Potentially very, very useful for Khabib to know.