The deploy website does not say that the plugin creates hashes.
The only mention of hashes is on the Introduction page which says:
As a repository contains more than the artifacts (POMs, the metadata, MD5 and SHA1 hash files...), deploying means not only copying the artifacts, ...
This suggests that the hash files are merely copied by the plugin, whereas in fact the plugin creates them.
Please could the docs be updated to clarify that the plugin actually creates the hashes?