This was his defense. I don't know exactly what code he took, of course. Here's what known:
- GS cites "500 million lines of code". This is most certainly including all dependencies (I deal with HFT systems and usually they are not _that_ complicated), so it is probably correct that 99% of the code was indeed open source.
- He uploaded the tarball with the code to his "server in Germany" (Hetzner, I presume). Sounds scary to the judges, but of course, having a server at Hetzner is perfectly normal.
- He deleted .bash_history. Quite a red flag for me.
And anyway, why repack and upload open source code as a tarball?
BTW, here's what Goldman Sachs published on Github: https://github.com/goldmansachs (GS Collections are well-known, but not a lot of code expected from a big company).