diff --git a/pkgs/tools/text/groff/site.tmac b/pkgs/tools/text/groff/site.tmac
index 8ef1040ca4a..776a7abb1da 100644
--- a/pkgs/tools/text/groff/site.tmac
+++ b/pkgs/tools/text/groff/site.tmac
@@ -14,3 +14,6 @@
 .  if '\V[GROFF_SGR]'' \
 .    output x X tty: sgr 0
 .\}
+.
+.ds doc-default-operating-system Nixpkgs
+.ds doc-volume-operating-system Nixpkgs