I checked gpgmeqt and its decrypt_verify_from_filename. It uses PartialFileGuard and no remaining output file on verification error.

I have changed the places where tfry made suggestions and made some additional changes and pasted this into the description. There still need to be made some more changes.

@pl13 Thank you very much for your testing.

After discussion various other wordings like:

Since the signing certificate is not marked as verified, the data cannot be trusted to originate from the right source, either. Technically, signature and data match.

I found this hard to read. Suggestion: "Technically, signature and data match, but the signing certificate is not marked as verified. The data cannot be trusted to originate from the stated source."

It occurred to me that users may find the wording "evaluated FILE with signature" strange, because if you have a paper document you check the signature and not the content of the file.
Opinions?

Test results with the same files as in my last comment and the updated patch:
In cases 2 and 4 where no compression and no --chunk-size was used, and a
later tag was modified the output file still remains.
In all other cases no output file (with or without .part) remains.

There was no veto for the removal of the color. I'll update the description.

Noteworthy changes in Version 5.0.2 (2026-03-16)

Thanks again for further testing of yours.

I tested following cases with a 100~mb file (GnuPG 2.5.20 on linux):

I'd like to push the changes above for gpg, even if it's not exactly same as what Kleo does (not perfect enough: when signature check fails, output file remains;).

I found that for a signed+encrypted file, when AEAD failure occurs in the stream of signature part (after literal data part), output file remains.
It's also the case when signature (which comes after literal data packet) is wrong.