Webkit (along with Safari) was started under Avie Tevanian's watch. Scott Forstall worked under him and Bertrand Serlet, along with Lisa Melton, who lead the development team for Webkit. Forstall was responsible for the development and release of Apple Maps.
I'm pretty sure Melton credited Forstall with giving with the support and cover for safari/khtml - she's written extensively about it.
https://donmelton.com/2013/01/10/safari-is-released-to-the-w...
And for Apple Maps, I remember reading somewhere that one reason Forstall refused to sign the infamous apology letter was that the initial release was from a team not directly under his supervision, but I can't find the old reference to that...granted, whatever went down was probably a joint failure of everyone involved