diff --git a/src/build_system.ml b/src/build_system.ml
index ec3987180aea..ac23598c0af3 100644
--- a/src/build_system.ml
+++ b/src/build_system.ml
@@ -194,7 +194,7 @@ module Alias0 = struct
 
   let dep_rec_internal ~name ~dir ~ctx_dir =
     Build.lazy_no_targets (lazy (
-      File_tree.Dir.fold dir ~traverse_ignored_dirs:false ~traverse_vendored_dirs:false
+      File_tree.Dir.fold dir ~traverse_data_only_dirs:false ~traverse_vendored_dirs:false
         ~init:(Build.return true)
         ~f:(fun dir acc ->
           let path = Path.Build.append_source ctx_dir (File_tree.Dir.path dir) in
@@ -1256,7 +1256,7 @@ and get_rule t path =
 let all_targets t =
   String.Map.to_list t.contexts
   |> List.fold_left ~init:Path.Build.Set.empty ~f:(fun acc (_, ctx) ->
-    File_tree.fold t.file_tree ~traverse_ignored_dirs:true ~traverse_vendored_dirs:true ~init:acc
+    File_tree.fold t.file_tree ~traverse_data_only_dirs:true ~traverse_vendored_dirs:true ~init:acc
       ~f:(fun dir acc ->
         match
           load_dir
diff --git a/src/dune_load.ml b/src/dune_load.ml
index fccc34ee3e52..ebb2d0d837ca 100644
--- a/src/dune_load.ml
+++ b/src/dune_load.ml
@@ -258,7 +258,7 @@ let interpret ~dir ~project ~ignore_promoted_rules
 let load ?(ignore_promoted_rules=false) ~ancestor_vcs () =
   let ftree = File_tree.load Path.Source.root ~ancestor_vcs in
   let projects =
-    File_tree.fold ftree ~traverse_ignored_dirs:false ~traverse_vendored_dirs:true ~init:[]
+    File_tree.fold ftree ~traverse_data_only_dirs:false ~traverse_vendored_dirs:true ~init:[]
       ~f:(fun dir acc ->
         let p = File_tree.Dir.project dir in
         if Path.Source.equal
diff --git a/src/file_tree.ml b/src/file_tree.ml
index 2f757d0a8267..cf3133816608 100644
--- a/src/file_tree.ml
+++ b/src/file_tree.ml
@@ -136,19 +136,19 @@ module Dir = struct
     String.Map.foldi (sub_dirs t) ~init:Path.Source.Set.empty
       ~f:(fun s _ acc -> Path.Source.Set.add acc (Path.Source.relative t.path s))
 
-  let skip ~traverse_ignored_dirs ~traverse_vendored_dirs t =
+  let skip ~traverse_data_only_dirs ~traverse_vendored_dirs t =
     match t.status with
-    | Data_only -> not traverse_ignored_dirs
+    | Data_only -> not traverse_data_only_dirs
     | Vendored -> not traverse_vendored_dirs
     | Normal -> false
 
-  let rec fold t ~traverse_ignored_dirs ~traverse_vendored_dirs ~init:acc ~f =
-    if skip ~traverse_ignored_dirs ~traverse_vendored_dirs t then
+  let rec fold t ~traverse_data_only_dirs ~traverse_vendored_dirs ~init:acc ~f =
+    if skip ~traverse_data_only_dirs ~traverse_vendored_dirs t then
       acc
     else
       let acc = f t acc in
       String.Map.fold (sub_dirs t) ~init:acc ~f:(fun t acc ->
-        fold t ~traverse_ignored_dirs ~traverse_vendored_dirs ~init:acc ~f)
+        fold t ~traverse_data_only_dirs ~traverse_vendored_dirs ~init:acc ~f)
 
   let rec dyn_of_contents { files; sub_dirs; dune_file } =
     let open Dyn in
@@ -397,7 +397,7 @@ let files_recursively_in t ~prefix_with path =
   match find_dir t path with
   | None -> Path.Set.empty
   | Some dir ->
-    Dir.fold dir ~init:Path.Set.empty ~traverse_ignored_dirs:true ~traverse_vendored_dirs:true
+    Dir.fold dir ~init:Path.Set.empty ~traverse_data_only_dirs:true ~traverse_vendored_dirs:true
       ~f:(fun dir acc ->
         let path = Path.append_source prefix_with (Dir.path dir) in
         String.Set.fold (Dir.files dir) ~init:acc ~f:(fun fn acc ->
diff --git a/src/file_tree.mli b/src/file_tree.mli
index dde6388a22b8..5c603f282192 100644
--- a/src/file_tree.mli
+++ b/src/file_tree.mli
@@ -50,7 +50,7 @@ module Dir : sig
 
   val fold
     :  t
-    -> traverse_ignored_dirs:bool
+    -> traverse_data_only_dirs:bool
     -> traverse_vendored_dirs:bool
     -> init:'a
     -> f:(t -> 'a -> 'a)
@@ -77,12 +77,12 @@ val load
   -> ancestor_vcs:Vcs.t option
   -> t
 
-(** Passing [~traverse_ignored_dirs:true] to this functions causes the
+(** Passing [~traverse_data_only_dirs:true] to this functions causes the
     whole source tree to be deeply scanned, including ignored
     sub-trees. *)
 val fold
   :  t
-  -> traverse_ignored_dirs:bool
+  -> traverse_data_only_dirs:bool
   -> traverse_vendored_dirs:bool
   -> init:'a
   -> f:(Dir.t -> 'a -> 'a)
diff --git a/src/upgrader.ml b/src/upgrader.ml
index 29edd94b839b..9c0fceffc7da 100644
--- a/src/upgrader.ml
+++ b/src/upgrader.ml
@@ -374,7 +374,7 @@ let upgrade ft =
     ; to_edit = []
     }
   in
-  File_tree.fold ft ~traverse_ignored_dirs:false ~traverse_vendored_dirs:false ~init:()
+  File_tree.fold ft ~traverse_data_only_dirs:false ~traverse_vendored_dirs:false ~init:()
     ~f:(fun dir () -> upgrade_dir todo dir);
   let git = lazy (
     match Bin.which ~path:(Env.path Env.initial) "git" with
diff --git a/src/utop.ml b/src/utop.ml
index 3d9782863b51..944407b151df 100644
--- a/src/utop.ml
+++ b/src/utop.ml
@@ -26,7 +26,7 @@ let libs_under_dir sctx ~db ~dir =
   (let open Option.O in
    let* dir = Path.drop_build_context dir in
    let+ dir = File_tree.find_dir (Super_context.file_tree sctx) dir in
-   File_tree.Dir.fold dir ~traverse_ignored_dirs:true ~traverse_vendored_dirs:true
+   File_tree.Dir.fold dir ~traverse_data_only_dirs:true ~traverse_vendored_dirs:true
      ~init:[] ~f:(fun dir acc ->
        let dir =
          Path.Build.append_source (Super_context.build_dir sctx)