IDA is tool for reverse engineering binaries. It works by allowing people to annotate and reinterpret raw data into code and structures that make sense. It's the tool that allows us to know what certain parts of the code do, and allows us to analyse pieces of code to figure out what they so. IDA stores all this information in a database, which has the file extension IDB. Until recently, knizz was maintaining the FireRed database (which he did a huge amount of work on). Since he left, I have taken over that role so that others can easily share in our knowledge.