diff --git a/lib/BUILD.bazel b/lib/BUILD.bazel
index dce61bd2b..44b312801 100644
--- a/lib/BUILD.bazel
+++ b/lib/BUILD.bazel
@@ -31,6 +31,7 @@ bool_flag(
     build_setting_default = True if is_bzlmod_enabled() else False,
 )
 
+# TODO(3.0): change default to True.
 bool_flag(
     name = "tar_compute_unused_inputs",
     build_setting_default = False,