diff --git a/pkgs/build-support/kernel/make-initrd-ng/README.md b/pkgs/build-support/kernel/make-initrd-ng/README.md
index 741eba67e43f..d92b7eab7fe1 100644
--- a/pkgs/build-support/kernel/make-initrd-ng/README.md
+++ b/pkgs/build-support/kernel/make-initrd-ng/README.md
@@ -38,6 +38,9 @@ object is copied depends on its type.
    - If it is *also* an ELF file, then all of its direct shared
      library dependencies are also listed as objects to be copied.
 
+   - If an unwrapped file exists as `.[filename]-wrapped`, then it is
+     also listed as an object to be copied.
+
 2. A directory's direct children are listed as objects to be copied,
    and a directory at the same absolute path in the initrd is created.