diff --git a/src/nix/flake.md b/src/nix/flake.md
index 2b999431c..b3321441c 100644
--- a/src/nix/flake.md
+++ b/src/nix/flake.md
@@ -666,6 +666,11 @@ following fields:
   other attributes are necessary because they provide information not
   stored in the store path.
 
+  The attributes in `locked` are considered "final", meaning that they are the only ones that are passed via the arguments of the `outputs` function of a flake.
+  For instance, if `locked` contains a `lastModified` attribute while the fetcher does not return a `lastModified` attribute, then the `lastModified` attribute will be passed to the `outputs` function.
+  Conversely, if `locked` does *not* contain a `lastModified` attribute while the fetcher *does* return a `lastModified` attribute, then no `lastModified` attribute will be passed.
+  If `locked` contains a `lastModifed` attribute and the fetcher returns a `lastModified` attribute, then they must have the same value.
+
 * `flake`: A Boolean denoting whether this is a flake or non-flake
   dependency. Corresponds to the `flake` attribute in the `inputs`
   attribute in `flake.nix`.