window.location.search returns the query string part of the current URL.

All that bit of code is doing is ensuring the frame on the page gets passed the query string the outer page had.

E.g. https://www.google.com/foobar/?hello -> https://foobar.withgoogle.com/?hello

My guess is that they have set up some pattern matching or keyword matching against search queries for some particular programming questions related to whatever they are hiring for. NLP, maybe?