Definition of the number of users in OAuth

[JMC1]

What is the definition of the number of OAuth users?

I am creating an add-on on the Google Cloud Marketplace. When I apply for the add-on, an item called "OAuth consent screen" is displayed. At this time, the upper limit of the number of OAuth users is listed, and it says "100 users maximum."

Does the number of users here refer to one account? Or does one domain count as one account?

Also, does it not count if the app is just installed?

I would like to know under what conditions a user is counted as one user in the OAuth section.