Another possibility: the numbers might be part of the name. Like Speed 5Test as in the fifth version of a testing framework. But again, no known information on such a framework.
He knew the risks. At 4est, your perception could outrun your body. At 5est, your perception could outrun causality . You might see your own death three seconds before it happened, but be unable to stop it. You might reach for a door handle and find your hand passing through it because you were already a microsecond out of phase. speed 5est extra quality
Speed isn't just bandwidth; it's response time. Your ISP's DNS is usually slow. Another possibility: the numbers might be part of the name
Multi-player gaming, 4K video streaming, huge file downloads. 40-100 Mbps 4K video streaming