Not sure if this is the right place to put this, but here goes anyway.
Some challenges I like. I can run fleets against them over and over. They’re fun. I want to keep them available to throw stuff at.
Some challenges I hate. Usually various spam fleets, or stuff that just looked good to start and turned into a slog. No fun. I want to burn them from my poor computer’s memory.
Is there a way for me to purge individual challenges from my “Downloaded” list, without clearing out the whole thing?
I’m afraid not. I guess it might be handy to have that capability though. Or to tag challenges with keywords.
Well darn. But at least I’ve put the bug in your ear about it. I’ll take the victories I can get. 
Okay, me poking around and probably getting myself into trouble:
In My Documents\My Games\GratuitousSpaceBattles\web\challenges, there are a slew of files with challenge numbers as names (at least I’m assuming those are challenge numbers; the files are .gsb files). I don’t suppose that I might be able to selectively purge my downloaded challenges list by doing the grunt work to dig up the challenge numbers I don’t like and just delete those files? Or would that start some sort of cascading meltdown that causes my hard drive to melt through the desk, the floor, and part of the basement below? (Or, y’know, just screw up the game, that would be bad too.)
Could someone who actually understands how the magic inside the tower case works give me some guidance? Thanks.
Removing the lines from the list would work more than deleteing the gsbs. They are ignroed unless needed.