Meaning of lines in "wcap" that don't have a MAC, and are not "beacon" or "wep" broadcasts?
Those remaining lines are very important metadata measured from the radio/baseband software to help troubleshooting issues with wireless that can crop up in cases of interference, lack of signal and to identify the hardware / media access layers of the network connection between the radio on your Mac and the radio on the access point.

In these specific lines, you have 802.11a (a less common protocol), and very good signal to noise ratios, the exact channel you are tuned in to and the basic data rate / encoding rate for the link between your Mac and the radio at the access point.

These data would be very helpful if you were seeing large numbers of errors or retransmits or didn’t know which base station you were connecting to.