Is visitor data merged into user data after login?

Hi!

Is the data collected before a user logs in automatically associated with that user (post login)?

Thanks,
Michael

From How are requests with a User ID tracked? FAQ - Analytics Platform - Matomo:

When a visitor connects to your website but is not initially logged in, their visit is associated with a Visitor ID by default. This is a unique identifier for that specific visit that is not attributed to a specific user. However, once that user logs into their account and you set a User ID for this visitor, then all actions such as page views are linked to the User ID and not the visitor ID. Any previously tracked action for this visitor before the user was logged in is also associated with this User ID.

When a user logs in, Matomo counts all actions before and after logging in as one user, one visit, and one unique visitor.