Can you please give insight regarding who controls the editing of wallet software and core network software? How are changes approved?
Anyone can edit the wallet software to their liking and the decision as to whether those changes are approved, is by network participants choosing to (or not) updating their wallet code.
The Nano Foundation happen to be the organisation that is professionally focused on protocol development, and work with the community to find ways to improve the source code. Typically nodes owners will accept updates put forward by the core development team.
Check out Github to see some of this in action: Nano · GitHub
I will also add that you can review some details about Contributing to the core node/wallet code in the docs here: Contributing to the Nano Node - Nano Documentation. We are looking to improve and put more structure around change suggestion and management, but for the time being discussions are often best done here in the forums or in a GitHub issue as @Andy_Johnson noted.
Thank you so much for the information