Devenv.sh - How to get ${pkgs.devenv-profile}?

I want to set the PATH explicitly so it does not include all my regular PATH entries. I tried using <nixpkgs>.devenv-profile yielding error: value is a path while a set was expected and ${pkgs.devenv-profile} yielding error: attribute 'devenv-profile' missing. Yet, something like ${pkgs.git} works fine.

I am clearly misunderstanding something…