That’s that speed the ports are capable of. 10/100/1000 megabits per second. Most things with an Ethernet port nowadays are 10/100/1000 capable, and 2.5Gb is becoming reasonably common.
Weirdly, Roku and other smart TVs are often only 100Mb capable since 4k streaming only requires about 60Mb and if you are squeezing pennies a 1Gb port is a bit more expensive.
10Gb is just starting to get available for high end consumer devices.