Support --secret flag setting x-kde-passwordManagerHint

[yorickvP]

Some password managers, like kde wallet and keepassxc, mark copied passwords as "secret", by
offering the mimetype x-kde-passwordManagerHint with the value secret.
This stops clipboard managers from saving passwords in history, and optionally stops KDE Connect from forwarding this clipboard data to other devices.

It would be nice to have support for this in wl-clipboard, so I can safely use it to copy passwords from my password store. Adding arbitrary multi-mime copy seems complicated, but it should be easy to add a flag to mark copy data as secret.

[bugaevc]

Hm, sounds like a good idea indeed, thanks for bringing it to my attention!

It's kind of a shame that this is KDE-specific, I'd prefer a more generic solution at the Wayland protocol level. But on the other hand wl-clipboard has never shied away from making use of GTK- and wlroots-specific protocols, so why not support a KDE-specific MIME type as well.

It would probably make sense to also expose this is in wl-paste --watch as CLIPBOARD_STATE=sensitive in the new CLIPBOARD_STATE protocol, which is about to be released in 2.2.0. So the flag should probably be named --sensitive as well.

[yorickvP]

I'm currently using this patch

[Cybso]

I wrote a similar request at https://bugs.kde.org/show_bug.cgi?id=487359 yesterday and was referred to the x-kde-passwordManagerHint. Is there any chance that this pull request gets merged into main?