I'm unable to verify this trivia that M8xtor added on Feburary 15th, 2019 due to the general lack of coverage about Ukur, keeping it here for verification.
"Ancient Mesopotamians used to construct "cult statues" out of various of materials to house spirits. Each cult statue went through a ritual where the statue was given "life" and it's mouth "was opened" and washed so they could see and eat. The UGU in INFRA has one open eye as well as an open mouth ready for a sacrifice."
-Gabe
In addition, I'd like to make a theory based off of dialogue in Open Sewer, as well as the arguably supernatural events that occur in the ARG in general, that "Ukur" may be the entity that is supposedly keeping people in Stalburg trapped underground. How this correlates to the Machine, SMV, and the "Red Raven" is still vague, but based on its seemingly sacrificial nature, it may be a device used to sacrifice homeless people to Ukur in exchange for Stalburg's prosperity, or some kind of blessing.