+INPUT FORMAT
+------------
+
+Git sends the remote helper a list of commands on standard input, one
+per line. The first command is always the 'capabilities' command, in
+response to which the remote helper must print a list of the
+capabilities it supports (see below) followed by a blank line. The
+response to the capabilities command determines what commands Git uses
+in the remainder of the command stream.
+
+The command stream is terminated by a blank line. In some cases
+(indicated in the documentation of the relevant commands), this blank
+line is followed by a payload in some other protocol (e.g., the pack
+protocol), while in others it indicates the end of input.
+
+Capabilities
+~~~~~~~~~~~~
+
+Each remote helper is expected to support only a subset of commands.
+The operations a helper supports are declared to git in the response
+to the `capabilities` command (see COMMANDS, below).
+
+'option'::
+ For specifying settings like `verbosity` (how much output to
+ write to stderr) and `depth` (how much history is wanted in the
+ case of a shallow clone) that affect how other commands are
+ carried out.
+
+'connect'::
+ For fetching and pushing using git's native packfile protocol
+ that requires a bidirectional, full-duplex connection.
+
+'push'::
+ For listing remote refs and pushing specified objects from the
+ local object store to remote refs.
+
+'fetch'::
+ For listing remote refs and fetching the associated history to
+ the local object store.
+
+'import'::
+ For listing remote refs and fetching the associated history as
+ a fast-import stream.
+
+'refspec' <refspec>::
+ This modifies the 'import' capability, allowing the produced
+ fast-import stream to modify refs in a private namespace
+ instead of writing to refs/heads or refs/remotes directly.
+ It is recommended that all importers providing the 'import'
+ capability use this.
++
+A helper advertising the capability
+`refspec refs/heads/{asterisk}:refs/svn/origin/branches/{asterisk}`
+is saying that, when it is asked to `import refs/heads/topic`, the
+stream it outputs will update the `refs/svn/origin/branches/topic`
+ref.
++
+This capability can be advertised multiple times. The first
+applicable refspec takes precedence. The left-hand of refspecs
+advertised with this capability must cover all refs reported by
+the list command. If no 'refspec' capability is advertised,
+there is an implied `refspec {asterisk}:{asterisk}`.
+
+Capabilities for Pushing
+~~~~~~~~~~~~~~~~~~~~~~~~
+'connect'::
+ Can attempt to connect to 'git receive-pack' (for pushing),
+ 'git upload-pack', etc for communication using the
+ packfile protocol.
++
+Supported commands: 'connect'.
+
+'push'::
+ Can discover remote refs and push local commits and the
+ history leading up to them to new or existing remote refs.
++
+Supported commands: 'list for-push', 'push'.
+
+If a helper advertises both 'connect' and 'push', git will use
+'connect' if possible and fall back to 'push' if the helper requests
+so when connecting (see the 'connect' command under COMMANDS).
+
+Capabilities for Fetching
+~~~~~~~~~~~~~~~~~~~~~~~~~
+'connect'::
+ Can try to connect to 'git upload-pack' (for fetching),
+ 'git receive-pack', etc for communication using the
+ packfile protocol.
++
+Supported commands: 'connect'.
+
+'fetch'::
+ Can discover remote refs and transfer objects reachable from
+ them to the local object store.
++
+Supported commands: 'list', 'fetch'.
+
+'import'::
+ Can discover remote refs and output objects reachable from
+ them as a stream in fast-import format.
++
+Supported commands: 'list', 'import'.
+
+If a helper advertises 'connect', git will use it if possible and
+fall back to another capability if the helper requests so when
+connecting (see the 'connect' command under COMMANDS).
+When choosing between 'fetch' and 'import', git prefers 'fetch'.
+Other frontends may have some other order of preference.
+
+'refspec' <refspec>::
+ This modifies the 'import' capability.
++
+A helper advertising
+`refspec refs/heads/{asterisk}:refs/svn/origin/branches/{asterisk}`
+in its capabilities is saying that, when it handles
+`import refs/heads/topic`, the stream it outputs will update the
+`refs/svn/origin/branches/topic` ref.
++
+This capability can be advertised multiple times. The first
+applicable refspec takes precedence. The left-hand of refspecs
+advertised with this capability must cover all refs reported by
+the list command. If no 'refspec' capability is advertised,
+there is an implied `refspec {asterisk}:{asterisk}`.
+