I don't know but my guess would be anything that isn't core storage - we know they run their own SAN on their own hardware because that was the cause of another outage a month or two ago.
At a guess:
- Bitbucket Pipelines
- Webhook workers
- Front-end web servers
- SSH push/pull workers
Basically anything that's elastic to demand. Presumably the cost of AWS storage makes it not worth it for the Bitbucket team.
