Configuration
Point Nix at Vega in one place.
Add the substituter and public key to /etc/nix/nix.conf (or the equivalent NixOS nix.settings):
extra-substituters = https://vega-cache.dev
extra-trusted-public-keys = vega-cache-1:cPagS1g69NQGwlBCyTTeKav/NhlN8a7ixuj2uLOkHrQ=
Mirrored Nixpkgs paths keep their cache.nixos.org-1 signature, which Nix already trusts, so the key above is only needed for Vega-built outputs.
Vega is read-only and mirror-only today. The authenticated write path is gated behind independent build verification (see Reproducibility).