In a nutshell I believe what you are referring to is a methodology to protect an entity from copyright infringement when creating software. Specifically, when creating software to take the place of existing licensed software. It involves using a 2 team approach to first identify everything a piece of software or code does, then recreate it from scratch only utilizing its actual function.

Example. You have a piece of software that sorts widgets by size and color. Your software is no longer able to be licensed.

You bring in a team to look at the existing software to see exactly what it does. You document what you put in to it and what it provides you.

You pass that information to a second team who uses only those limited parameters to create something new that does the same exact thing.

The end result is product that duplicated the function of the original but is protected from copyright infringement because of the documented way you had it created.

Type env in your user

some env for all user and other environment you add in your user

you can use unset env for delete env