nixos/lib: Clarify that nixos.evalModules impl is NOT experimental

nixos/lib/eval-config-minimal.nix

@@ -31,7 +31,12 @@ let
     prefix ? [],
     modules ? [],
     specialArgs ? {},
-  }: lib.evalModules {
+  }:
+  # NOTE: Regular NixOS currently does use this function! Don't break it!
+  #       Ideally we don't diverge, unless we learn that we should.
+  #       In other words, only the public interface of nixos.evalModules
+  #       is experimental.
+  lib.evalModules {
     inherit prefix modules;
     specialArgs = {
       modulesPath = builtins.toString ../modules;

nixos/lib/eval-config.nix

@@ -33,7 +33,11 @@ let pkgs_ = pkgs;
 in
 
 let
-  evalModulesMinimal = (import ./eval-config-minimal.nix { inherit lib; bypassEvalModulesWarning = true; }).evalModules;
+  evalModulesMinimal = (import ./default.nix {
+    inherit lib;
+    # Implicit use of feature is noted in implementation.
+    featureFlags.minimalModules = { };
+  }).evalModules;
 
   pkgsModule = rec {
     _file = ./eval-config.nix;