I disagree with my sibling comment. The trick is beautiful. If you generate UUIDs such that each bit in the result can be reliably traced back to a single bit in the input, then you can take a substring of the UUID and use that to infer which bits of the input integer must be set to produce that substring. So you can produce a whole list of input bytes that meet the criteria and those become your search results.

The real magic trick here is that the uuids on the page only look random to us because of some bit twiddling and XOR trickery. If we had a better intuition for such things we would notice that successive UUIDs are just as correlated as successive integers.

Elegant stuff