Function bound_base 

pub fn bound_base(response: &Value, requested: &str) -> String

The base revision the node says the change is actually bound to.

Creation is idempotent, so a retry that resolved a base_ref which has since moved reuses the existing change at its original base. Reporting the requested revision there would describe a workspace that does not exist: the orchestrator would record one base while the change is bound to another, and every later comparison against it would be wrong. The node’s answer is authoritative; requested is only a fallback for a response that carries none.