It's a 6 pin connector. From the text below it, it's for connecting a programming cable - presumably this is some kind of custom keyboard where you can change the firmware.
Lacking any other information, I'd assume it is something like a pin header.
From the wikipedia page:
It might not be a pin header, though. There are all kinds of connectors out there. If you don't have the PCB layout or a picture or drawing of the finished board, then you're kind of stuck.
It is a connector, looking at the pinout most likely a programming connector. The actual connector depends on the footprint of P1.
Most programming connectors use set of header pins, either male or female.
Male is most likely.
It is a connector, but it doesn't have to be there. It depends on whether you plan to use it and what kind of connector you plan on connecting to it.
You can simply leave 6 through-hole contacts on the board.
These contacts are used if you want to do some in-circuit programming.
By convention, a "P" designation on a schematic or wiring diagram indicates a plug. A plug is by IEEE/ANSII conventions the movable part of a connection, or the more movable part. The fixed/less movable part is designated by a "J", for jack.
So if you have a board that going to plug into a motherboard, the connector on the board is designed as P-xxx, and the connector on the motherboard is designated as J-yyy, where xxx and yyy are numbers.
Similarly, if you have a cable that plugs into a chassis or box (like an Ethernet cable plugging into your PC), the connector on the cable is a plug (P), while the connector on the PC is a jack (Jack).