You Already Know
This was a simple warmup challenge. We were told that, if we could read the challenge description, we already knew the flag.
Indeed, opening Chromium's developer tools and inspecting the responses of the XHR request to retrieve the description
in the scoreboard, the flag was hidden in plain sight inside a React comment. Really, we already knew.

Original writeup (https://mhackeroni.it/archive/2018/05/20/defconctfquals-2018-all-writeups.html#you-already-know).