comma-separated names are supplied, the first name affects the transfer
checksums, and the second name affects the pre-transfer checksums (bf(-c)).
-The algorithm choices are "auto", "xxhash", "MD5", "MD4", and "none".
+The algorithm choices are "auto", "xxh64" (aka "xxhash"), "MD5", "MD4", and "none".
If "none" is specified for the first (or only) name, the bf(--whole-file) option
is forced on and no checksum verification is performed on the transferred data.
If both the client and the server are at least version 3.2.0, they will
exchange a list of checksum names and choose the first one in the list that
they have in common.
-This typically means that they will choose xxhash if they both support it
+This typically means that they will choose xxh64 if they both support it
and fall back to MD5.
If one side of the transfer is not new enough to support this checksum
negotation, then a value is chosen based on the protocol version (which