Thanks, clear for me now!

Ok, they are differentiated with the number. What does that mean now, can I use the name tag and name the holes by their number as it's done in countless mapped courses, or not? Sorry, I'm still confused....

Thanks, I will respect it.
Even so, I beleive the hole# is indeed the name of the hole. Some golf courses name their holes in addidtion with fancy names. Most do not and simply name their holes with numbers. On the score card, the holes are named by the number, too. Otherwise, how can holes be differentiated. However, I'm far from an expert and sure will respect it.

Since ref tag is not visible, and hole# is visible information, I have added hole#.
If that violates OSM mapping rules, I sure wil take it off. However, I did not find respective information in the link provided. So, I'm a bit confused.

When the hole has a name, I use the name. Otherwise, I put in the hole# for better orientation. What would be the reason for not putting in the hole#?

Thanks, it's all cleaned up.

The changes will be deleted in a few days.
I am mapping out the nearby former golf course, as long as it is still kind of visible in OSM. The reason for adding cartpaths on to the taxi way's is, that in the golf course mapping tool, where the data will be finally imported in, the taxi ways are not imported. However, the taxi ways are part of the scenery around the old golf course. All the added data will be deleted and changes to the golf course boarder line will be put back in the original state. Note, that no changes have been done to any of the airport taxi ways. The original situation will be reestablished within a few days.