This is common when naming data centers. I know many have not worked in hardware infra these days if you were born into the cloud world, but in the old days it was not uncommon to name a data center after the nearest airport code, much like we now use cloud regions.

cf-ray is the Cloudflare ray id, which ends with the airport code for the colo that served the response. They're airport codes, but that's just to show the nearest city.

Mine is ending with IST, which is the new Istanbul airport, weird indeed.

Wow mine ends in EWR...that's the newark airport which is not the closest, but a close airport to me. Hmm

Yep, mine says YUL -- Montreal's airport.

The acronym is probably Cloudflare's edge

Yeah mine is showing ATL