diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -1055,7 +1055,6 @@
     'ManiphestTaskListView' => 'applications/maniphest/view/ManiphestTaskListView.php',
     'ManiphestTaskMailReceiver' => 'applications/maniphest/mail/ManiphestTaskMailReceiver.php',
     'ManiphestTaskOpenStatusDatasource' => 'applications/maniphest/typeahead/ManiphestTaskOpenStatusDatasource.php',
-    'ManiphestTaskOwner' => 'applications/maniphest/constants/ManiphestTaskOwner.php',
     'ManiphestTaskPHIDType' => 'applications/maniphest/phid/ManiphestTaskPHIDType.php',
     'ManiphestTaskPriority' => 'applications/maniphest/constants/ManiphestTaskPriority.php',
     'ManiphestTaskPriorityDatasource' => 'applications/maniphest/typeahead/ManiphestTaskPriorityDatasource.php',
@@ -4373,7 +4372,6 @@
     'ManiphestTaskListView' => 'ManiphestView',
     'ManiphestTaskMailReceiver' => 'PhabricatorObjectMailReceiver',
     'ManiphestTaskOpenStatusDatasource' => 'PhabricatorTypeaheadDatasource',
-    'ManiphestTaskOwner' => 'ManiphestConstants',
     'ManiphestTaskPHIDType' => 'PhabricatorPHIDType',
     'ManiphestTaskPriority' => 'ManiphestConstants',
     'ManiphestTaskPriorityDatasource' => 'PhabricatorTypeaheadDatasource',
diff --git a/src/applications/maniphest/constants/ManiphestTaskOwner.php b/src/applications/maniphest/constants/ManiphestTaskOwner.php
deleted file mode 100644
--- a/src/applications/maniphest/constants/ManiphestTaskOwner.php
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-
-final class ManiphestTaskOwner extends ManiphestConstants {
-
-  const PROJECT_NO_PROJECT = 'PHID-!!!!-NO-PROJECT';
-
-}