Not sure where you meant to print untrusted stuff checks

Thanks, later

Some keyring packages also use which instead of command -v to check presence of a command. Non-POSIX.

in a POSIX sh

I believe this package belongs in contrib, as its only use-case is with together with software outside of Debian main.

on mailing list. I agree, forgot to set the section earlier.

Lots of silly stuff like programming errors (loops only looping once) easily caught by ShellCheck in some archive packages. Heh.

I just also noticed ubuntu-keyring does not respect apt-config's Dir::Etc::trustedparts.

Please tell me there's some nicer way to do this. I don't know if I want to be so verbose about /etc/ changes in this scenario:

TRUSTEDPARTS="/etc/apt/trusted.gpg.d"
eval "$(apt-config shell TRUSTEDPARTS Dir::Etc::trustedparts/f)"

# start of debconf(1)
. /usr/share/debconf/confmodule

# APT system trusted key configuration (asks: should the keys also be
# installed to the /etc/apt/trusted.gpg.d directory?)
M_A_KEYRING="matrix-archive-keyring.gpg"
db_get matrix-archive-keyring/apt-trustedparts
if [ "$RET" = true ]; then
    # Install the keyring to APT.
    if [ -w "$TRUSTEDPARTS/$M_A_KEYRING" ] && \
        [ ! -L "$TRUSTEDPARTS/$M_A_KEYRING" ];
    then
        echo "$TRUSTEDPARTS/$M_A_KEYRING will now be a symbolic link" \
            "to /usr/share/keyrings/$M_A_KEYRING" >&2
    fi
    ln -fs "/usr/share/keyrings/$M_A_KEYRING" "$TRUSTEDPARTS/"
else
    # Remove the keyring from APT.
    if [ -w "$TRUSTEDPARTS/$M_A_KEYRING" ] && \
        [ ! -L "$TRUSTEDPARTS/$M_A_KEYRING" ];
    then
        echo "Removing $TRUSTEDPARTS/$M_A_KEYRING, it's in the way" >&2
    fi
    rm -f "$TRUSTEDPARTS/$M_A_KEYRING"
fi

Well, I cleaned it up. There's a debconf(1) question if the keys should be installed to /etc/apt/trusted.gpg.d now. Only thing remaining is sources.list(5).

In reply to @lindalap:matrix.org

Some keyring packages also use which instead of command -v to check presence of a command. Non-POSIX.

Maximus: It's not done yet. The "yes/no" answer doesn't install matrix-org.list to your sources.list.d, but everything else is done.

Would you still like to give it a test? You can upgrade later once it's released in Debian.

I'll be eating my meal and adding the four lines (?) of shell script to make that happen in few hours.

(and a Make rule to create the sources.list)