[Over at the Debian BTS](https://bugs.debian.org/907290), David Bremner points out that the apt-key manpage, on Debian stable, says > Instead of using this [add] [sub]command a keyring should be placed > directly in the /etc/apt/trusted.gpg.d/ directory with a > descriptive name and either "gpg" or "asc" as file extension. So ISTM that `Apt.trustsKey` should be implemented simply with `File.hasContents`, i.e., the property should delete any old `.gpg` file and then create a `.asc` file with the text string content of the `AptKey`. --spwhitton