This is a free-text description field (descr) on a MountInstFsmStage object, holding whatever descriptive text was set for one individual stage/step inside that NFS-mount FSM task. An admin uses it to record human-readable context about that specific MountInstFsmStage instance so its purpose is clear without having to infer it from IDs alone. For example, an admin auditing MountInstFsmStage objects would read this field to see the notes attached to one particular instance rather than a generic label shared by all of them.