Hmmm... can't find anything else on that apart from the mention in that blog post. Is there more detail anywhere?
They also implicitly state that it's not Shor's which is (to the best of my knowledge) the most effective integer factorisation algorithm for general purpose QCs currently know.
They also say that they "have a factoring algorithm". They don't say that it's actually implemented on running hardware.
I also notice the complete lack of clarification on the followup question that poked on the explicit "executed it on real hardware" question ;-)