I happened to have done some research in this, maybe you won't understand this but maybe the devs see use in it:
I saw in the json file that there's a steam ID for every user.
So it could be possible with use of the Steam API, but only if the game has been played by the player within the last 2 weeks, because the AppID of Renegade X is the one of Unreal Development Kit, and it's not listed as a game, and therefore doesn't show with the GetOwnedGames functions, it only shows with the GetRecentlyPlayed function.
The next and biggest problem is that those steam IDs start with 0x0, which is a different steamID format than the one the API needs (SteamID64). On the other hand you do get the correct profile when you paste that ID in the url: steamcommunity.co/profiles/"0x0xxxxxxxxxxxxxxx (the ID)", I went as far as this, maybe the steam64ID shows up somewhere when you load this, but haven't been able to/had time to check that out yet.
Maybe there's a way to convert those ID's starting with 0x0 to the Steam64ID, the one that the Steam API needs, haven't found a way yet.