If you’re interested in the one he’s just started (oasis): it’s a default map included in the experimental branch of Timberborn. The previous one that was super tiny is a community map you can download from steam workshop (called ‘Ant hill’ I believe). The ‘zoo escape’ one is also on steam workshop but is no longer quite the same version that he used.

If I remember correctly, he normally mentions it in the first video of a series