I don’t believe it’s water as he has similar subs marked with ln2. I think this guy is trolling.
LE:
It’s the other guy, my bad:
https://hwbot.org/submission/4318542_gbp_superpi___32m_core_i9_9900ks_5min_7sec_933ms
has the other subs with ln2 at lower freq, but some are marked on water.