Most of what you want is in `Database.java`, but if you want to fix the IP range whitelisting to support IPv6, that is in the core folder
I recommend eclipse or inteliJ for Java development. Please do not try and push IDE specific files.
## If you want to work on frontend features
All webdev files are in the root of the directory. I recommend something like VSCode or Atom for web development (tip: you can open an entire folder with atleast VSCode for easy switching between files)