Yep!
Download the (Offline PICO-8 Carts) version, and just open “terra-itch.p8” in a text editor.
Keep in mind, though, it’s written in PICO-8’s variation of Lua, and is quite compressed. It will take a bit of effort to make sense of it even if you’re familiar with the language’s quirks.
I tried to leave as many comments intact as I could fit, so good luck :)