Gossipsub is an implementation of pubsub based on meshsub and floodsub. You can read the specification here. libp2p-gossipsub currently implements the v1.1 of the spec.
JASM is an assembler/disassembler for JVM bytecode. It provides a nice syntax for writing JVM classes in a bytecode-focused assembly language, and can also disassemble any Java .class file to JASM ...