Toolbox for analyzing and editing pkg application files for psp,ps3, ps4 and ps5, includes the most useful functions you might need.
PKG Viewer by Loopayeh: view PS3/PS4/PS5 package info and cover art
A decompilation of Bloodborne (CUSA03173 v1.09) with its own runtime: the game's code rewritten as readable C++, one verified function at a time. The game doesn't run on it yet; 21 functions verified. No game files included.
PS4 PKG → FFPFSC