"the speed of light could have been faster during the early universe"
I'm an idiot.
If it were me, I would look at that idea and say : "okay, so it might have been different. No way to prove it, why bother ?".
But these guys went on and not only wrote out their theory but claim to have a test that can prove it. And they're putting that up in front of a community of people who are very capable of putting said theory to the test and either thoroughly trashing it or conclusively proving it, or somewhere in the middle where proof is not definite but could be possible if some more intelligent people could be found to find out.
And I, the caveman, can only look on and wonder who will bring an answer to these questions while all I'm capable of doing is wash the dishes.
Kudos to these enlightened people who have questions that I couldn't even begin to ask myself. Whatever the answer, you will have improved Humanity's understanding of the Universe, and that's more than I will ever be capable of.