The information added to the switch table from incoming frames includes primarily the source MAC address of the device that sent the frame and the port number on which the frame was received. Additionally, if VLANs are configured, the VLAN ID is also recorded. Some switches add a timestamp for maintaining entries, but the core information learned and added for forwarding decisions is the source MAC address associated with the incoming port. This allows the switch to map devices to specific ports and efficiently forward frames to their destinations without flooding the network unnecessarily.