Jason Levine aka PK is credited as the editor for Technical Grappling, and also co-writer (with Sean Punch) of Furious Fists, the 3rd book in the GURPS Action series. Also wrote Allies, book 5 in the Dungeon Fantasy series.
His forum profile describes him as "Assistant GURPS Line Editor" and his signature says "Reverend Pee Kitty of the Order Malkavian-Dobbsian" linking to Twitter and Live Journal and Mygurps and https://gamingballistic.com/2016/06/02/transcript-hunter-and-pk-talk-after-end/ (video itself is gone).