in the meleerumble.txt file, there seems to be a typo in line 128 (my version of that file). It has to be PARTICIPANTSURL=https://robowiki.net/wiki/RoboRumble/Participants/Melee?action=raw
Note the questionmark between Melee and action.
Thank you, I remember myself comparing the two links but turns out my eyes couldn't distinguish between "&" and "?". :)