If the FBI wants carriers to install software on their network devices, the FBI is implementing regulatory law as code in the network substrate. The source and its build and development process must be public. They have no magic tricks and there is no unknown capability that this could compromise. It's simply a requirement for a country governed by the law. It's how we watch the watchers.
Seeing as how we can't even get voting machine source code released, I have little faith that the spy state will cede its code in the near future. Given this, it's now time for all able-minded hackers to build tools for personal liberty and spread them far and wide. Godspeed.