@gniibe Am I misunderstanding something? I thought that with this change one is able to connect from a Windows box to a Linux box and have GPG agent forwarding work. I am still hitting pretty much the same issue described here: https://github.com/PowerShell/Win32-OpenSSH/issues/1564
On my Windows endpoint I'm running gpg.exe version 2.4.0.49237 and in C:\Users\mate\AppData\Roaming\gnupg\gpg-agent.conf I have a single line enable-win32-openssh-support. Running gpg-connect-agent.exe reloadagent /bye I have a gpg-agent running. Get-Process gpg-agent shows that it's running. In my Windows env I have SSH_AUTH_SOCK set to \\.\pipe\openssh-ssh-agent and my Linux endpoint is configured in SSH config with

ForwardAgent yes
AddKeysToAgent yes
RemoteForward /run/user/1015/gnupg/S.gpg-agent C\:/Users/mate/AppData/Local/gnupg/S.gpg-agent.extra

As the remote end reports /run/user/1015/gnupg/S.gpg-agent that socket for agent-socket when issuing gpgconf --list-dirs and my local gpgconfg.exe --list-dirs reports C%3a\Users\mate\AppData\Local\gnupg\S.gpg-agent.extra where I transform %3a to \: manually. SSH authentication works perfectly, when connecting pinentry-qt pops up to unlock my key and when connecting to yet another machine, my SSH agent is forwarded again. However, gpg fails to use my agent. Issuing gpg --list-secret-keys --verbose prints the following to the console:

gpg --list-secret-keys --verbose
gpg: using pgp trust model
getsockopt SO_ERROR failed
connect_to C:/Users/mate/AppData/Local/gnupg/S.gpg-agent.extra port -2: failed.
gpg: no running gpg-agent - starting '/usr/bin/gpg-agent'
getsockopt SO_ERROR failed
connect_to C:/Users/mate/AppData/Local/gnupg/S.gpg-agent.extra port -2: failed.
gpg: waiting for the agent to come up ... (5s)
getsockopt SO_ERROR failed
connect_to C:/Users/mate/AppData/Local/gnupg/S.gpg-agent.extra port -2: failed.
getsockopt SO_ERROR failed
connect_to C:/Users/mate/AppData/Local/gnupg/S.gpg-agent.extra port -2: failed.
getsockopt SO_ERROR failed
connect_to C:/Users/mate/AppData/Local/gnupg/S.gpg-agent.extra port -2: failed.
getsockopt SO_ERROR failed
connect_to C:/Users/mate/AppData/Local/gnupg/S.gpg-agent.extra port -2: failed.
getsockopt SO_ERROR failed
connect_to C:/Users/mate/AppData/Local/gnupg/S.gpg-agent.extra port -2: failed.
getsockopt SO_ERROR failed
connect_to C:/Users/mate/AppData/Local/gnupg/S.gpg-agent.extra port -2: failed.
gpg: waiting for the agent to come up ... (4s)
gpg: waiting for the agent to come up ... (3s)
gpg: waiting for the agent to come up ... (2s)
gpg: waiting for the agent to come up ... (1s)
gpg: can't connect to the agent: End of file

What is missing to tie the knot on both ends without having to resort to 3rd party tools like @rupor-github 's agent-gui? The remote gpg version is 2.2.19, is that the issue? Must that also be 2.3.9+?

Thanks. I fixed the documentation. Will go into 1.19

I guess we need some gpgme support as well.

How with --status-fd passed to gpgtar we will get these progress lines:

I am adding gpgcom, as a tag, the first minimal task would be to create such a page with the debug output from gpgconf -X with options to copy / or save them to a file. Not sure if that should be a subtask, because on the other hand this would be a start of this "Debug Tab"

What I need in particular is a way to get the output of gpgconf -X.

Those "curated keyrings" and keyservers don't work together. The whole idea of automated but curated keyrings is dead end.

Note to self: This cannot be fixed easily because inserting the updated certificates (the details dialog triggers a listing of the certificate with full details) into the key cache is implemented as removal followed by add (with the corresponding model signals).

To fix this we also need to fix our key selection test (key-selection.scm) which is can't cope with all combinations. The tests are run with a faked time of 2004-01-01 on all subsets of this ordered list of keys

See also T4713