The speed of light and second are now DEFINED, so you can no longer correctly say the "error in measuring the speed of light." But what amounts to the same thing is the length of a meter, which has been measured with an error of about 1/10 of this error. So larger than we would expect, but not incredibly large. And whether it would have cosmological significance, where most numbers [which are not just SWAG] range from order of magnitude estimates to no better than two significant figures is very doubtful.
True, that!
Just didn't want some "layman" (snark) to dismiss it as being entirely insignificant. But my hyperbole was admittedly inappropriate.
Regards,