And I believe made by some of the people that formerly worked on Descent.
For example, you approach a "T" junction, and depending on your pitch angle, the branches may be up/down or left/right. But since there's no natural ground or sky, you can either maintain an orientation memory (I usually did automatically), or you can just let all that go and travel with no sense of true orientation.
Occasionally you reach an area with some signs or printed panels, and then you realize what the regional up/down orientation was; but it didn't matter in zero gravity.
He's the creator of three.js, and it looks like this uses that for rendering instead of being a straight port.
WebGL1 WASM version based on https://github.com/dxx-rebirth/dxx-rebirth -> https://midzer.de/wasm/descent1/
And Quake for web by the same author: https://mrdoob.github.io/three-quake/