arxiv has an endorsement system, where
during the submission process, we may require authors who are submitting papers to an archive or subject class for the first time to get an endorsement from another arXiv author
However, I submitted a paper to arxiv for the first time, and I was not asked for an endorsement. The relevant help page says:
During the initial deployment of the system, we may also give automatic endorsements to submitters from known academic institutions.
So this may be what happened to me (I have a verified email address from an academic institution), but this seems weird, because it says “during the initial deployment of the system”, and this is dated 2004.
So: does someone know what is the current endorsement policy for arxiv?
I believe the help page describes the current endorsement policy. You may also have fallen into the category described by "We may give some people automatic endorsements based on topic, previous submissions, and academic affiliation."
As I understand it, most people are in that category and never see the endorsement system in action. In practice, it seems to get applied to cranks and to people who look like they might possibly be cranks (e.g., people with no academic affiliation, or who are writing on controversial topics).