There's now a command-line option to make Pageant open an AF_UNIX
socket at a pathname of your choice. This allows it to act as an SSH
agent for any client program willing to use a WinSock AF_UNIX socket.
In particular, this allows WSL 1 processes to talk directly to Windows
Pageant without needing any intermediate process, because the AF_UNIX
sockets in the WSL 1 world interoperate with WinSock's ones.
(However, not WSL 2, which isn't very surprising.)