Are Cloudflare Ray IDs persistent web identifiers?

Cloudflare assigns "Ray IDs" to anyone who runs a request through their service, which apparently runs on 80% of websites in the world and receives 1/10th of all online requests.

Does that Ray ID only last as long as a user is on a site in a single usage session, or does the Cloudflare Ray ID follow users around permanently by assessing their IP Address, User Agent, and local Autonomous System Number?

Does the Ray ID change if you alter …

cloudflare ids persistent privacy web