Bad documentation
In this challenge we need to find a password that was apparently leaked on github.
Vulnerability
We can go through the erased files in the previous commits. The most interesting one is an image:

We notice the Authorization header with a value of basic. This means a username/password is available in the following base64 and indeed we have:
admin:PCTF{t0_c0D3's_3VuR}_R3aLlY_G0n3}
Flag
PCTF{t0_c0D3's_3VuR}_R3aLlY_G0n3}