David Bürgin:
I should have just tried before asking! Thank you. This works:add_header all Checker-Version SpamAssassin _VERSION_ (_SUBVERSION_) on mail.mydomain.ch And voilà: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on mail.mydomain.ch
A final remark: This solution has a side effect. It changes the order of inserted headers so that X-Spam-Checker-Version is now the last instead of the first X-Spam- header … … all right then.
