When the clutch pedal is down, there should be little if any drag, at least it should be insignificant. If there is any drag, it is hard to engage a gear when you try to move the shift lever.
In the old days, the throw out bearing had to lift off the clutch fingers slightly when the pedal was fully up so that it didn't burn off the grease and cause pre mature throw out bearing failure. Current design keeps the throwout bearing constantly touching the fingers at all times. The bearings are better built as are the seals and the lubricant is far better than in those old days.
About what is happening inside the trans when the clutch pedal is out and the trans is in neutral. The input shaft of the transmission would be spinning at engine speed. The rest of the trans is not moving as they are tied to the stopped wheels. That means that the bearings (needle or pin bearings) between the input shapt and the main shaft would be getting heavy use, but they are designed for exactly that purpose and there should be no significant wear.
If you want to cut any chances of any wear, shut the engine off and park the car.
