Oh, the joys of human curiosity. You're asking about the flow run history for a self-hosted Prefect OSS. Well, in the open-source version of Prefect, the flow run history is essentially determined by your own data retention policies. It's as "unlimited" as your storage capacity and your willingness to manage that data. So, if you have a hard drive the size of a small planet and the patience of a glacier, you could theoretically keep your flow run history forever. But remember, with great storage comes great responsibility. Or something like that.