diff --git a/README.md b/README.md
index 9b621a0..c394586 100644
--- a/README.md
+++ b/README.md
@@ -237,6 +237,7 @@ Note that you shouldn't call `overrideAttrs` on a derivation built by Naersk
 | `root` | Used by `naersk` to read the `Cargo.toml` and `Cargo.lock` files. May be different from `src`. When `src` is not set, `root` is (indirectly) used as `src`. |
 | `gitAllRefs` | Whether to fetch all refs while fetching Git dependencies. Useful if the wanted revision isn't in the default branch. Requires Nix 2.4+. Default: `false` |
 | `gitSubmodules` | Whether to fetch submodules while fetching Git dependencies. Requires Nix 2.4+. Default: `false` |
+| `additionalCargoLock` | Additional cargo lock used to specify crates required for build |
 | `cratesDownloadUrl` | Url for downloading crates from an alternative source Default: `"https://crates.io"` |
 | `cargoBuild` | The command to use for the build. The argument must be a function modifying the default value. <br/> Default: `''cargo $cargo_options build $cargo_build_options >> $cargo_build_output_json''` |
 | `cargoBuildOptions` | Options passed to cargo build, i.e. `cargo build <OPTS>`. These options can be accessed during the build through the environment variable `cargo_build_options`. <br/> Note: naersk relies on the `--out-dir out` option and the `--message-format` option. The `$cargo_message_format` variable is set based on the cargo version.<br/> Note: these values are not (shell) escaped, meaning that you can use environment variables but must be careful when introducing e.g. spaces. <br/> The argument must be a function modifying the default value. <br/> Default: `[ "$cargo_release" ''-j "$NIX_BUILD_CORES"'' "--message-format=$cargo_message_format" ]` |
diff --git a/config.nix b/config.nix
index 1dfbad1..c926b02 100644
--- a/config.nix
+++ b/config.nix
@@ -37,6 +37,7 @@ let
     # 2.4+.
     gitSubmodules = attrs0.gitSubmodules or false;
 
+    # Additional cargo lock used to specify crates required for build
     additionalCargoLock = attrs0.additionalCargoLock or null;
 
     # Url for downloading crates from an alternative source