If we take relativity at face value, the speed of light is c = 2.997 x 10^8 <<<locally>>>. <<<Globally>>> the speed of light can be anything. Cosmologists talk about the universe expanding faster than light during the inflationary phase, which sounds confusing because we're told nothing can move faster than light. While it is true that the speed of light must propogate at only one velocity for all freely moving frames of reference, the speed at which space itself expands can be anything! Relativity does not restrict the speed at which space itself expands or contracts. TL;DR The maximum local speed of anything moving through space in a freely moving frame of reference is c. The speed at which space itself expands or contracts is not limited in any way by Einstein's theory and is consistent with observations of the the inflationary universe in which the universe expanded at faster than the speed of light.
I like to think of it as the speed of information. The quickest any information can move from point A to point B is c. (Even if those points are themselves moving.)
The universe can expand faster than c because there is not actually any information moving between the center and the perimeter.
