Uh, you stumbled across Apple’s network stack.
About Skywalk
Skywalk en0 = Ethernet?
S5L8940XI2CController = leftover files? Pertaining to the A5 chip/I²C interface
AppleBCMWLANInterfacePCIe = Apple/Broadcom Wireless LAN Interface over PCI Express
Skywalk Tx = Transmission stuff