I suspect this leak was made by the author themselves and submitted to 4chan via Tor or a VPN. I don't have hard evidence to back this up but if you read the Wikipedia article about them, it's pretty easy to put two and two together.
Further, the conclusion about Jenkins being the attack vector is drawn without much thought or explanation, and it is also interesting that they've used the same attack vector elsewhere.
I follow her on Tumblr and I assure you this is not the case. She's very ebullient and loves answering questions about her hacking.
(Unironically keep slaybossing, OP)
Kind of seals it. I admire their brazenness.
4chan blocks both Tor and VPNs. It's a terrible place to leak things, but a hacker can most probably find innocuous IPs.
Costs $20 per year and can be paid with various cryptocurrencies. Since 4chan keeps IP logs, this seems like a good deal for someone leaking company source code.