diff --git a/pageserver/src/tenant/timeline/detach_ancestor.rs b/pageserver/src/tenant/timeline/detach_ancestor.rs
index 1970efdb8c..893ad7dbee 100644
--- a/pageserver/src/tenant/timeline/detach_ancestor.rs
+++ b/pageserver/src/tenant/timeline/detach_ancestor.rs
@@ -670,9 +670,6 @@ pub(super) async fn prepare(
         .start_new_attempt(detached)
         .await?;
 
-    // FIXME: is the assumption that no one else is making these changes except us strong
-    // enough...? need a witness in the RemoteTimelineClient api?
-    //
     // if it wasn't persistently started already, mark the ancestor detach persistently started.
     detached
         .remote_client