SHA256 is a one-way hashing function. Which means that feeding that sentence into SHA-256 and it starting with the characters in that sentence is very unlikely chance.

They probably wrote a script that tacked on a bunch of random letters and numbers to a sentence, then hashed it via brute force until it returned a hash that started with the exact same thing that the sentence said.

This is similar to how Bitcoin's proof of work algorithm.

It's self-referential and that makes it non-obvious how it's accomplished. Changing the sentence changes the hash, which also changes the sentence. So in any case it's an interesting construction.

Another potential issue that comes to mind is the usage of "short hashes" as an identifier instead of the full hash.