Ghidra, NSA's reverse-engineering tool
Why this is important (for those uninitiated):- Ghidra is basically the first real competitor to IDA Pro, the extremely expensive and often pirated state-of-the-art software for reverse engineering. Nothing else has come close to IDA Pro.- Ghidra is open-source, IDA Pro is not.- Ghidra has a lot of really cool features that IDA Pro doesn't, such as decompiling binaries to pseudo-C code.- It's also collaborative, which is interesting because multiple people can reverse engineer the same binary at the same time -- something IDA only got VERY recently.