I just tried to add the NetRunner Debian repo (after figuring out its location from a recent screenshot posted here) to my current Debian + Neon mixed system, but I cannot seem to be able to find the GPG signing key used by that archive.
As I’ve done everything short of downloading the actual installation ISO, could somebody please post the output of:
apt-key export 0x03C715C8BAB85BBB
on their system?
Disclaimer: Yes, yes, I know this isn’t an official installation method, etc. But please just let me shoot into my own foot the way I like it most. Thanks! 
BTW: To add the latest NetRunner archives to a Debian system create a file named /etc/apt/sources.list.d/netrunner.list with the following contents (they won’t be very usable without a signing key however):
deb http://deb.netrunner.com/dci/packages/netrunner netrunner-desktop-1908 calamares ds9-artwork ds9-common extras netrunner-desktop netrunner backports