Have nixpkgs use registry version

[tlelson]

I set my nix registry to the version used to build the system so that anytime i build a flake it doesn't download a new tar ball.

However when I devbox init i can see it does not follow the system nixpkgs and fetches an unknown hash. In fact it seems to get a couple of version of nixpkgs.

Here is my registry:

› nix registry list | grep nixpkgs
system flake:nixpkgs path:/nix/store/vawkv67jxh8kl4flrqgpcsmn9inqgvjv-source?lastModified=1741862977&narHash=sha256-prZ0M8vE/ghRGGZcflvxCu40ObKaB%2Bikn74/xQoNrGQ%3D&rev=cdd2ef009676ac92b715ff26630164bb88fec4e0
global flake:nixpkgs github:NixOS/nixpkgs/nixpkgs-unstable

Here is the output of a recent devbox init:

› devbox add python terraform tflint tflint-plugins.tflint-ruleset-google google-cloud-sdk
Ensuring nixpkgs registry is downloaded.
Downloaded 'github:NixOS/nixpkgs/0d534853a55b5d02a4ababa1d71921ce8f0aee4c?narHash=sha256-IDtwLhWMKvydW9GrB6ETwhij%2Bvma0hYHln8pR/rTd%2BU%3D' to '/nix/store/8r2xs1kc
cx7kk1kmgi24kivfjxx67gl7-source' (hash 'sha256-IDtwLhWMKvydW9GrB6ETwhij+vma0hYHln8pR/rTd+U=').
Ensuring nixpkgs registry is downloaded: Success
Info: Adding package "python@latest" to devbox.json
Ensuring nixpkgs registry is downloaded.
Downloaded 'github:NixOS/nixpkgs/573c650e8a14b2faa0041645ab18aed7e60f0c9a?narHash=sha256-4thdbnP6dlbdq%2BqZWTsm4ffAwoS8Tiq1YResB%2BRP6WE%3D' to '/nix/store/0yw40qnr
ar3lvc5hax5n49abl57apjbn-source' (hash 'sha256-4thdbnP6dlbdq+qZWTsm4ffAwoS8Tiq1YResB+RP6WE=').
Ensuring nixpkgs registry is downloaded: Success
Info: Adding package "terraform@latest" to devbox.json
Info: Adding package "tflint@latest" to devbox.json
Info: Adding package "tflint-plugins.tflint-ruleset-google@latest" to devbox.json
Info: Adding package "google-cloud-sdk@latest" to devbox.json
Info: Installing the following packages to the nix store: terraform@latest, tflint@latest, tflint-plugins.tflint-ruleset-google@latest, google-cloud-sdk@latest, pyt
hon@latest

Is it possible to use the registry version of nixpkgs?