particular ref, where <ref> is the full name of a ref on the
server.
+If the 'sideband-all' feature is advertised, the following argument can be
+included in the client's request:
+
+ sideband-all
+ Instruct the server to send the whole response multiplexed, not just
+ the packfile section. All non-flush and non-delim PKT-LINE in the
+ response (not only in the packfile section) will then start with a byte
+ indicating its sideband (1, 2, or 3), and the server may send "0005\2"
+ (a PKT-LINE of sideband 2 with no payload) as a keepalive packet.
+
The response of `fetch` is broken into a number of sections separated by
delimiter packets (0001), with each section beginning with its section
header.