The only way to know this would be if you read the entire discussion across 2+ threads on the Gitlab site for their event tracking MR. Basically this whole shit show started as so:
* Gitlab previously used 3rd party infrastructure for their user event tracking
* They did not send this 3rd party user id for GDPR and other reasons
* Because they did not have user id, they could not understand user behavior across sessions. Understanding user behavior across sessions is important, so they wanted to add it.
* Gitlab had just finished moving their event tracking infrastructure in house.
* The original MR was to add user id as an attribute to their event tracking
What proceeded was what I consider a very reasonable back and forth between data, infrastructure, and legal on the correct way to add user id. But somewhere along the line it went off the rails. How it turned from simply adding user id into including Pendo JS tags for on-prem customers, I have no idea.