Merge docs/usage updates from 'pre-0.75' branch.

doc/config.but

@@ -3389,13 +3389,13 @@ will be impossible.
 
 This is an SSH-1-specific bug.
 
-\H{config-psusan} The \q{Bare \cw{ssh-connection}} protocol
+\H{config-psusan} The \q{Bare \cw{\i{ssh-connection}}} protocol
 
 In addition to SSH itself, PuTTY also supports a second protocol that
 is derived from SSH. It's listed in the PuTTY GUI under the name
 \q{Bare \cw{ssh-connection}}.
 
-This protocol consists of just the innermost of SSH's three layers: it
+This protocol consists of just the innermost of SSH-2's three layers: it
 leaves out the cryptography layer providing network security, and it
 leaves out the authentication layer where you provide a username and
 prove you're allowed to log in as that user.
@@ -3417,7 +3417,7 @@ network namespace.
 
 Explicit support for this protocol is new in PuTTY 0.75. As of
 2021-04, the only known server for the bare \cw{ssh-connection}
-protocol is the Unix program \cq{psusan} that is also part of the
+protocol is the Unix program \cq{\i{psusan}} that is also part of the
 PuTTY tool suite.
 
 (However, this protocol is also the same one used between instances of
@@ -3428,6 +3428,10 @@ possible to connect another instance of PuTTY directly to that Unix
 socket, by entering its pathname in the host name box and selecting
 \q{Bare \cw{ssh-connection}} as the protocol!)
 
+Many of the options under the SSH panel also affect this protocol,
+although options to do with cryptography and authentication do not,
+for obvious reasons.
+
 I repeat, \s{DON'T TRY TO USE THIS PROTOCOL FOR NETWORK CONNECTIONS!}
 That's not what it's for, and it's not at all safe to do it.
 

doc/index.but

@@ -195,6 +195,11 @@ saved sessions from
 \IM{protocol selection} selecting a protocol
 \IM{protocol selection} choosing a protocol
 
+\IM{ssh-connection} bare \cw{ssh-connection} protocol
+\IM{ssh-connection} \cw{ssh-connection} protocol, bare
+
+\IM{psusan} \cq{psusan} program
+
 \IM{login name}{username} login name
 \IM{login name}{username} user name
 \IM{login name}{username} account name

doc/man-pageant.but

@@ -294,6 +294,25 @@ with the \cw{--encrypted} option.)
 (This may leave some keys in cleartext, if they were not previously
 added with the \cw{--encrypted} option.)
 
+\dt \cw{--test-sign} \e{key-identifier}
+
+\dt \cw{--test-sign-with-flags=}\e{flags} \e{key-identifier}
+
+\dd Sign arbitrary data with the given key. This mode is only likely
+to be useful when testing \c{pageant} itself.
+
+\lcont{
+
+The data to sign is taken from standard input, signed by the agent
+with the key identified by \e{key-identifier}, and the resulting
+signature emitted on standard output (as a binary blob in the format
+defined by the SSH specifications).
+
+\e{flags} is a number representing a combination of flag bits defined
+by the SSH agent protocol.
+
+}
+
 \S{pageant-manpage-askpass} SSH-ASKPASS REPLACEMENT
 
 \dt \cw{--askpass} \e{prompt}
@@ -349,6 +368,19 @@ respectively. If neither option is given, Pageant will guess based on
 whether the environment variable \cw{SHELL} has a value ending in
 \cq{csh}.
 
+\dt \cw{--symlink} \e{fixed-path}
+
+\dd When operating in agent mode, as well as creating a uniquely named
+listening socket, \c{pageant} will also create (or update) a symbolic
+link at \e{fixed-path} pointing to that socket.
+
+\lcont{
+This allows access to an agent instance by setting the
+\c{SSH_AUTH_SOCK} environment variable to \e{fixed-path}, rather than
+having to use the value invented by \c{pageant} when it starts. It's
+mainly expected to be useful for debugging.
+}
+
 \dt \cw{--encrypted}, \cw{--no-decrypt}
 
 \dd When adding keys to the agent (at startup or later), keep them

doc/man-plink.but

@@ -56,6 +56,13 @@ to aid in verifying new files released by the PuTTY team.
 
 \dd Force serial mode.
 
+\dt \cw{-ssh-connection}
+
+\dd Force use of the \q{bare \cw{ssh-connection}} protocol. This is
+only likely to be useful when connecting to a \e{psusan(1)} server,
+most likely with an absolute path to a Unix-domain socket in place
+of \e{host}.
+
 \dt \cw{\-proxycmd} \e{command}
 
 \dd Instead of making a TCP connection, use \e{command} as a proxy;

doc/man-pscp.but

@@ -115,6 +115,19 @@ commands such as \q{\c{w}}).
 
 \dd Force use of SSH protocol version 2.
 
+\dt \cw{-ssh-connection}
+
+\dd Force use of the \q{bare \cw{ssh-connection}} protocol. This is
+only likely to be useful when connecting to a \e{psusan(1)} server,
+most likely with an absolute path to a Unix-domain socket in place
+of \e{host}.
+
+\dt \cw{-ssh}
+
+\dd Force use of the SSH protocol. (This is usually not needed; it's
+only likely to be useful if you need to override some other
+configuration of the \q{bare \cw{ssh-connection}} protocol.)
+
 \dt \cw{-4}, \cw{-6}
 
 \dd Force use of IPv4 or IPv6 for network connections.

doc/man-psftp.but

@@ -103,6 +103,19 @@ commands such as \q{\c{w}}).
 
 \dd Force use of SSH protocol version 2.
 
+\dt \cw{-ssh-connection}
+
+\dd Force use of the \q{bare \cw{ssh-connection}} protocol. This is
+only likely to be useful when connecting to a \e{psusan(1)} server,
+most likely with an absolute path to a Unix-domain socket in place
+of \e{host}.
+
+\dt \cw{-ssh}
+
+\dd Force use of the SSH protocol. (This is usually not needed; it's
+only likely to be useful if you need to override some other
+configuration of the \q{bare \cw{ssh-connection}} protocol.)
+
 \dt \cw{-4}, \cw{-6}
 
 \dd Force use of IPv4 or IPv6 for network connections.

doc/plink.but

@@ -71,7 +71,7 @@ use Plink:
 \c   -X -x     enable / disable X11 forwarding
 \c   -A -a     enable / disable agent forwarding
 \c   -t -T     enable / disable pty allocation
-\c   -1 -2     force use of particular protocol version
+\c   -1 -2     force use of particular SSH protocol version
 \c   -4 -6     force use of IPv4 or IPv6
 \c   -C        enable compression
 \c   -i key    private key file for user authentication

doc/pscp.but

@@ -55,6 +55,8 @@ use PSCP:
 \c   -l user   connect with specified username
 \c   -pw passw login with specified password
 \c   -1 -2     force use of particular SSH protocol version
+\c   -ssh -ssh-connection
+\c             force use of particular SSH protocol variant
 \c   -4 -6     force use of IPv4 or IPv6
 \c   -C        enable compression
 \c   -i key    private key file for user authentication
@@ -255,7 +257,7 @@ scripts: using \c{-batch}, if something goes wrong at connection
 time, the batch job will fail rather than hang.
 
 \S2{pscp-usage-options-backend}\i\c{-sftp}, \i\c{-scp} force use of
-particular protocol
+particular file transfer protocol
 
 As mentioned in \k{pscp-usage-basics}, there are two different file
 transfer protocols in use with SSH. Despite its name, PSCP (like many

doc/pubkeyfmt.but

@@ -124,7 +124,7 @@ passphrase:
 password-hashing function.
 
 The three integer values are used as parameters for Argon2, which
-allows you to configure the amount of memory used (in Kb), the number
+allows you to configure the amount of memory used (in Kbyte), the number
 of passes of the algorithm to run (to tune its running time), and the
 degree of parallelism required by the hash function. The salt is
 decoded into a sequence of binary bytes and used as an additional

doc/using.but

@@ -727,9 +727,8 @@ of these options:
 \b \i\c{-ssh} selects the SSH protocol.
 
 \b \i\c{-ssh-connection} selects the bare ssh-connection protocol.
-(This is only useful in specialised circumstances.)
-\#{FIXME: describe those circumstances somewhere in this manual,
-with reference to the psusan man page}
+(This is only useful in specialised circumstances; see \k{config-psusan}
+for more information.)
 
 \b \i\c{-telnet} selects the Telnet protocol.