Backported for VSD 3.4

Done. I've used the following script to create clear-signed test messages with good/bad signature signed with certificates with different validity and status (expired, revoked).

The behaviour might have changed a bit because of the ldap: prefix i use now, or i have missed this case the last time:
Given some cert on the "download" server, I can find it, if dirmngr.conf contains only the "download" server, or if the "download" server is listed first:

Independent of keyserver order in dirmngr.conf, --search-keys still offers keys from the upload server, but the download fails:

For "Although the upload server is used for upload, the gpg message still displays the first keyserver" see T8025

I assume, that testing the functionality is the only thing I can do here.

Looks good to me on gpg4win-5.0.0-beta479 @ win11.

I have verified (by looking at QTextEdit's code) that, on paste, QTextEdit splits the text for the internal representation into lines and discards any CR and LF characters.

It turns out that Kleopatra's notepad converts the CR characters of the spoofed file to LF characters when pasting the text so that Kleopatra doesn't really verify the content of the spoofed file but different content. And this results in a bad signature. The confusing bit is that Kleopatra also says "Successfully verified the notepad" and that it shows the claimed-to-be-signed text although the signature is bad which could lead an inattentive user to the assumption that the signature of the displayed text was actually good (because "Successfully verified").

There is always a warning about bad signature.

I think we are all wrong here. We were tricked by the fact that regardless of the outcome of the signature verification the signed content is shown. That is surprising for a cleartext signature because that one can be viewed anyway. Thus I propose to not update the clipboard unless the signature checks out.

I originally uploaded a wrong copy of the file. Now fixed; the correct checksum is 8d830a2dd7e1e14ecbc47b8cdc61d393e9d3f62c

On Linux, Kleopatra (master) with GnuPG 2.5 (master) shows a BAD signature. It shows the same output as running gpg --verify --output bla.txt in Konsole and pasting the file content (by maybe the copy paste changes some control characters). If I run gpg --verify --output bla.txt <payload.spoofed.asc then bla.txt also contains the same data.