Here’s a detailed breakdown of content regarding — including what they are, why they’re used, how to create them, and legal considerations. 1. What Is a PS1 PBP ROM? A PBP file ( .pbp ) is a compressed, multi-disc, and sometimes icon-packed format originally designed for PSP (PlayStation Portable) emulation of PlayStation 1 games. It stands for "PSP BIOS Package" or PlayStation Portable executable (later adapted for PS1 games via emulators like POPS ).