It has all the required files in the
GameMode Reference topic, and additionally a dts for a weapon and a png for the weapon icon. It also has namecheck.txt and a .cs file that is supposed to be exec'd by server.cs.
I didn't add more details because I can't think of anything relevant. The real clincher here is that I got it up and running with no errors and loading any default add-on I want via gamemode.txt; I just can't get it to run its own server.cs. I know server.cs is not running because I copy-pasted echoing a string literal like 30 times right at the start of the file.
Hypothetically if I made it two add-ons instead of one, with both being completely useless without the other, I'm pretty sure it would get failed on the RTB submission; I've been failed for
way less legitimate reasons than that.