even though the interface of IStorageRestorable.tpc_begin does not have a "status" argument, it is described in the notes below that the actual implementation uses it:
https://github.com/zopefoundation/ZODB/blob/0632974d/src/ZODB/interfaces.py#L950-L956
This is used by FileStorage:
https://github.com/zopefoundation/ZODB/blob/0632974d/src/ZODB/FileStorage/format.py#L30-L39
and the storage methods seem to accept this argument:
https://github.com/zopefoundation/ZODB/blob/0632974d/src/ZODB/BaseStorage.py#L182 https://github.com/zopefoundation/ZEO/blob/e5637818/src/ZEO/ClientStorage.py#L888 https://lab.nexedi.com/nexedi/neoppod/blob/fd87e153/neo/client/app.py#L473
Propagating the status fixes some cases where restoring commits did not recreate a storage that is byte-to-byte equivalent. This happened with a FileStorage that was packed and contained transactions with "p" status.