SCE devkit version 6.60 has a stub library display_stub.a available for users.
Along with stubs, this archive also has an object file userinterrupt.o which somehow has DWARF debug symbols from which I created the headers.
Obviously, the headers are missing lots of functions/structures declarations. Gotta add those from uOFW.
You can import the DWARF symbols into a Ghidra project with the types database.
It contains everything as extracted from the object file.