I brought my 2011 iMac in for repair, to replace a video card under an extended warranty program specific to my hardware configuration. (Reading between the lines, a cooling problem.) Once they got it on the testbench the tech decided to replace the system board as well because it tested faulty. At no charge! Despite the machine being a year+ out of warranty. Nice of them.
Anyway, a new system board means a new CPU, a new ethernet MAC, and a bunch of other small things. Which changed my machine’s identity for various things. I had to re-log in to all Apple online services. Time Machine also expressed concern but offered to “inherit” the backup I had, which seems to have worked. Had to set up a new IP assignment on my router for the MAC address of course.
I’d also logged Chrome out of Google and wiped all local state, for my security. Happy to report that logging back in to Chrome restored everything pretty well. I got all my Chrome extensions back but lost the extension configuration state. Also my browser link history is gone forever, I’d sort of hoped that would sync through Google too.