It's an RC file which is actually written, not a tmp file

This confusing variable name may come from a clip/paste

src/file_com.ml

@@ -42,11 +42,11 @@ open Core.Std;;
 type t = Settings_v.rc_file;;
 
 (* Function to write the rc file *)
-let write (tmp_file:t) =
+let write (rc_file:t) =
         (* Short name *)
         let name = !Const.rc_file in
         (* Create string to be written *)
-        let data = (Settings_j.string_of_rc_file tmp_file
+        let data = (Settings_j.string_of_rc_file rc_file
         |> Yojson.Basic.prettify ~std:true) in
         Out_channel.write_all (Lazy.force name) ~data
 ;;