I have an original Pixelbook (late 2017 release date) and the auto update support page [1] has been updated from June 2024 to June 2027 (with an asterisk saying it is user opt in but that's all I can see). So at first glance it doesn't seem to be paid.

My Pixelbook doesn't get much use anymore vs my M1 MacBook but it's nice to know it will still be supported. It can be a handy thin client and I don't have to worry as much about it getting stolen/abusing at this point in its life.

[1] https://support.google.com/chrome/a/answer/6220366?visit_id=...