Patchwork Quilt
We're provided with a download of the VScode source code, slightly modified. The name hinted at a patch happening, so I ran git diff and found a 'backdoor' leading to congonator.me/?id=ZmxhZ3tkb250X3RydXN0X2RvZGd5X2Rvd25sb2Fkc30%3D&key= when a key was pressed. I just decoded the id paramater, which revealed the flag.
flag{dont_trust_dodgy_downloads}