diff --git a/src/applications/base/PhabricatorApplication.php b/src/applications/base/PhabricatorApplication.php
index d29f0afde4..45909a92cd 100644
--- a/src/applications/base/PhabricatorApplication.php
+++ b/src/applications/base/PhabricatorApplication.php
@@ -411,7 +411,7 @@ abstract class PhabricatorApplication
    * To check if an application is installed //and// available to a particular
    * viewer, user @{method:isClassInstalledForViewer}.
    *
-   * @param string $class Application class name.
+   * @param class-string<PhabricatorApplication> $class Application class name.
    * @return bool   True if the class is installed.
    * @task meta
    */
@@ -427,7 +427,7 @@ abstract class PhabricatorApplication
    * To check if an application is installed at all, use
    * @{method:isClassInstalled}.
    *
-   * @param string $class Application class name.
+   * @param class-string<PhabricatorApplication> $class Application class name.
    * @param PhabricatorUser $viewer Viewing user.
    * @return bool True if the class is installed for the viewer.
    * @task meta
@@ -477,7 +477,7 @@ abstract class PhabricatorApplication
    * To check if an application is installed at all, use
    * @{method:isClassInstalled}.
    *
-   * @param string $class Application class name.
+   * @param class-string<PhabricatorApplication> $class Application class name.
    * @param PhabricatorUser|null $viewer Viewing user.
    * @return bool True if the class is installed or if the installed class is
    * available to the viewer when a viewer is given.
diff --git a/src/applications/calendar/worker/PhabricatorCalendarImportReloadWorker.php b/src/applications/calendar/worker/PhabricatorCalendarImportReloadWorker.php
index 8f27a814ab..ab389bdbac 100644
--- a/src/applications/calendar/worker/PhabricatorCalendarImportReloadWorker.php
+++ b/src/applications/calendar/worker/PhabricatorCalendarImportReloadWorker.php
@@ -31,6 +31,9 @@ final class PhabricatorCalendarImportReloadWorker extends PhabricatorWorker {
     $import_engine->importEventsFromSource($author, $import, false);
   }
 
+  /**
+   * @return PhabricatorCalendarImportQuery
+   */
   private function loadImport() {
     $viewer = PhabricatorUser::getOmnipotentUser();
 
diff --git a/src/applications/conduit/method/ConduitAPIMethod.php b/src/applications/conduit/method/ConduitAPIMethod.php
index 096c63fc9e..e63fab5319 100644
--- a/src/applications/conduit/method/ConduitAPIMethod.php
+++ b/src/applications/conduit/method/ConduitAPIMethod.php
@@ -230,14 +230,30 @@ abstract class ConduitAPIMethod
       ->loadClass($method_name);
   }
 
+  /**
+   * Whether to require a session key for calling the API method.
+   *
+   * @return bool Defaults to true
+   */
   public function shouldRequireAuthentication() {
     return true;
   }
 
+  /**
+   * Whether to allow public access. Related to the `policy.allow-public`
+   * global setting and policies set for the corresponding application.
+   *
+   * @return bool Defaults to false
+   */
   public function shouldAllowPublic() {
     return false;
   }
 
+  /**
+   * Whether not to guard writes against CSRF. See @{class:AphrontWriteGuard}.
+   *
+   * @return bool Defaults to false
+   */
   public function shouldAllowUnguardedWrites() {
     return false;
   }
@@ -316,6 +332,7 @@ abstract class ConduitAPIMethod
 
 
   /**
+   * @return AphrontCursorPagerView
    * @task pager
    */
   protected function newPager(ConduitAPIRequest $request) {
diff --git a/src/applications/herald/field/HeraldField.php b/src/applications/herald/field/HeraldField.php
index 0dd8686f96..d822f15eed 100644
--- a/src/applications/herald/field/HeraldField.php
+++ b/src/applications/herald/field/HeraldField.php
@@ -39,6 +39,11 @@ abstract class HeraldField extends Phobject {
     return null;
   }
 
+  /**
+   * @return array Conditions available in the dropdown after the object
+   *   dropdown as one of the CONDITION_* constants defined in the
+   *   HeraldAdapter class, rendered as e.g. "contains" or "is any of"
+   */
   public function getHeraldFieldConditions() {
     $standard_type = $this->getHeraldFieldStandardType();
     switch ($standard_type) {
@@ -157,6 +162,9 @@ abstract class HeraldField extends Phobject {
         $standard_type));
   }
 
+  /**
+   * @return bool
+   */
   abstract public function supportsObject($object);
 
   public function getFieldsForObject($object) {
diff --git a/src/applications/herald/value/HeraldEmptyFieldValue.php b/src/applications/herald/value/HeraldEmptyFieldValue.php
index ac81cb7d23..a7ac5ab85f 100644
--- a/src/applications/herald/value/HeraldEmptyFieldValue.php
+++ b/src/applications/herald/value/HeraldEmptyFieldValue.php
@@ -1,5 +1,10 @@
 <?php
 
+/**
+ * Implements not allowing to set a value for comparison in a boolean Herald
+ * rule condition (e.g. for "Assignee | does not exist") or in a boolean Herald
+ * rule action (e.g. "Do nothing" or "Require secure mail").
+ */
 final class HeraldEmptyFieldValue
   extends HeraldFieldValue {
 
diff --git a/src/applications/herald/value/HeraldFieldValue.php b/src/applications/herald/value/HeraldFieldValue.php
index 5ca88b56ee..bf7125df99 100644
--- a/src/applications/herald/value/HeraldFieldValue.php
+++ b/src/applications/herald/value/HeraldFieldValue.php
@@ -1,5 +1,11 @@
 <?php
 
+/**
+ * Implements the value to use for comparison in a Herald rule condition
+ * (e.g. the value which follows after "Assignee | is any of") and the value
+ * to set for a Herald rule action (e.g. what follows after "Add projects"
+ * or "Remove subscribers").
+ */
 abstract class HeraldFieldValue extends Phobject {
 
   private $viewer;
diff --git a/src/applications/lipsum/generator/PhabricatorTestDataGenerator.php b/src/applications/lipsum/generator/PhabricatorTestDataGenerator.php
index 470230aff5..4762922493 100644
--- a/src/applications/lipsum/generator/PhabricatorTestDataGenerator.php
+++ b/src/applications/lipsum/generator/PhabricatorTestDataGenerator.php
@@ -97,7 +97,7 @@ abstract class PhabricatorTestDataGenerator extends Phobject {
   /**
    * Get one random object by its PHP class name.
    *
-   * @param string $classname PHP class name.
+   * @param class-string $classname PHP class name.
    * @return PhabricatorLiskDAO Object of that class.
    */
   public function loadOneRandom($classname) {
diff --git a/src/applications/phid/type/PhabricatorPHIDType.php b/src/applications/phid/type/PhabricatorPHIDType.php
index a10e6167eb..188fbbb9b8 100644
--- a/src/applications/phid/type/PhabricatorPHIDType.php
+++ b/src/applications/phid/type/PhabricatorPHIDType.php
@@ -215,8 +215,10 @@ abstract class PhabricatorPHIDType extends Phobject {
   /**
    * Get all PHID types of an application.
    *
-   * @param string $application Class name of an application
-   * @return array<string, PhabricatorPHIDType> Map of constants of application
+   * @param class-string<PhabricatorApplication> $application Class name of an
+   *   application.
+   * @return array<string, PhabricatorPHIDType> Map of constants of
+   *   application.
    */
   public static function getAllTypesForApplication(
     string $application) {
diff --git a/src/applications/phrequent/storage/PhrequentTimeBlock.php b/src/applications/phrequent/storage/PhrequentTimeBlock.php
index 68ca563223..869b6d34fb 100644
--- a/src/applications/phrequent/storage/PhrequentTimeBlock.php
+++ b/src/applications/phrequent/storage/PhrequentTimeBlock.php
@@ -19,6 +19,9 @@ final class PhrequentTimeBlock extends Phobject {
     return $slices->getDuration($now);
   }
 
+  /**
+   * @return array<PhrequentTimeSlices>
+   */
   public function getObjectTimeRanges() {
     $ranges = array();
 
diff --git a/src/applications/policy/storage/PhabricatorPolicy.php b/src/applications/policy/storage/PhabricatorPolicy.php
index e9f1c09fa1..c9c89a9176 100644
--- a/src/applications/policy/storage/PhabricatorPolicy.php
+++ b/src/applications/policy/storage/PhabricatorPolicy.php
@@ -348,7 +348,7 @@ final class PhabricatorPolicy
    * policy. This is used to bulk load data (like project memberships) in order
    * to apply policy filters efficiently.
    *
-   * @param string $rule_class Policy rule classname.
+   * @param class-string $rule_class Policy rule classname.
    * @return list<wild> List of values used in this policy.
    */
   public function getCustomRuleValues($rule_class) {
diff --git a/src/applications/project/controller/PhabricatorProjectBoardController.php b/src/applications/project/controller/PhabricatorProjectBoardController.php
index 5427d1b93f..7afd5ba05c 100644
--- a/src/applications/project/controller/PhabricatorProjectBoardController.php
+++ b/src/applications/project/controller/PhabricatorProjectBoardController.php
@@ -5,6 +5,9 @@ abstract class PhabricatorProjectBoardController
 
   private $viewState;
 
+  /**
+   * @return PhabricatorWorkboardViewState
+   */
   final protected function getViewState() {
     if ($this->viewState === null) {
       $this->viewState = $this->newViewState();
@@ -22,6 +25,9 @@ abstract class PhabricatorProjectBoardController
       ->readFromRequest($request);
   }
 
+  /**
+   * @return AphrontDialogView
+   */
   final protected function newWorkboardDialog() {
     $dialog = $this->newDialog();
 
diff --git a/src/applications/project/controller/PhabricatorProjectBoardViewController.php b/src/applications/project/controller/PhabricatorProjectBoardViewController.php
index 5693f77511..ad40e7520d 100644
--- a/src/applications/project/controller/PhabricatorProjectBoardViewController.php
+++ b/src/applications/project/controller/PhabricatorProjectBoardViewController.php
@@ -7,6 +7,9 @@ final class PhabricatorProjectBoardViewController
     return true;
   }
 
+  /**
+   * @return AphrontResponse|PhabricatorStandardPageView
+   */
   public function handleRequest(AphrontRequest $request) {
     $viewer = $request->getUser();
 
@@ -400,6 +403,9 @@ final class PhabricatorProjectBoardViewController
     return $page;
   }
 
+  /**
+   * @return PHUIListItemView
+   */
   private function buildSortMenu(
     PhabricatorUser $viewer,
     PhabricatorProject $project,
@@ -473,6 +479,9 @@ final class PhabricatorProjectBoardViewController
     return $sort_button;
   }
 
+  /**
+   * @return PHUIListItemView
+   */
   private function buildFilterMenu(
     PhabricatorUser $viewer,
     PhabricatorProject $project,
diff --git a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
index 7f7e45139e..79d0ac628a 100644
--- a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
+++ b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
@@ -1036,7 +1036,7 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
   }
 
   /**
-   * @return int
+   * @return int|float Number of results to display (float if set to infinity)
    */
   public function getPageSize(PhabricatorSavedQuery $saved) {
     $bucket = $this->getResultBucket($saved);
diff --git a/src/applications/search/engineextension/PhabricatorSearchEngineExtension.php b/src/applications/search/engineextension/PhabricatorSearchEngineExtension.php
index 17ed59f35f..be44db38e0 100644
--- a/src/applications/search/engineextension/PhabricatorSearchEngineExtension.php
+++ b/src/applications/search/engineextension/PhabricatorSearchEngineExtension.php
@@ -72,6 +72,17 @@ abstract class PhabricatorSearchEngineExtension extends Phobject {
     return array();
   }
 
+  /**
+   * Add additional parameters to the $query based on elements in the $map
+   * @param $object A subclass of PhabricatorLiskDAO - a storage object, e.g.
+   *   ManiphestTask or PhabricatorDashboardPortal
+   * @param $query A corresponding subclass of
+   *   PhabricatorCursorPagedPolicyAwareQuery, e.g. ManiphestTaskQuery or
+   *   PhabricatorDashboardPortalQuery
+   * @param PhabricatorSavedQuery $saved
+   * @param array $map
+   * @return void
+   */
   public function applyConstraintsToQuery(
     $object,
     $query,
diff --git a/src/applications/search/ferret/PhabricatorFerretEngine.php b/src/applications/search/ferret/PhabricatorFerretEngine.php
index 3e4f04d866..7291d9c9ba 100644
--- a/src/applications/search/ferret/PhabricatorFerretEngine.php
+++ b/src/applications/search/ferret/PhabricatorFerretEngine.php
@@ -15,8 +15,8 @@ abstract class PhabricatorFerretEngine extends Phobject {
    */
   abstract public function getScopeName();
   /**
-   * @return string New instance of the corresponding
-   *   PhabricatorApplicationSearchEngine subclass
+   * @return PhabricatorApplicationSearchEngine New instance of the
+   *   corresponding PhabricatorApplicationSearchEngine subclass
    */
   abstract public function newSearchEngine();
 
diff --git a/src/applications/transactions/editengine/PhabricatorEditEngine.php b/src/applications/transactions/editengine/PhabricatorEditEngine.php
index 5520647bcd..1aee12a53a 100644
--- a/src/applications/transactions/editengine/PhabricatorEditEngine.php
+++ b/src/applications/transactions/editengine/PhabricatorEditEngine.php
@@ -102,6 +102,13 @@ abstract class PhabricatorEditEngine
     return $keys;
   }
 
+  /**
+   * Split the Full Key into its Edit Engine Key and its Form Key
+   *
+   * @param string $full_key 'Edit Engine Key/Form Key' string, e.g.
+   *   'macro.image/default' or 'maniphest.task/5'
+   * @return array<string,string> Edit Engine Key and Form Key
+   */
   public static function splitFullKey($full_key) {
     return explode('/', $full_key, 2);
   }
diff --git a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
index ed407f6fff..9aaf46c2d9 100644
--- a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
+++ b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
@@ -103,7 +103,8 @@ abstract class PhabricatorApplicationTransactionEditor
    *
    * Uninstalling the application will disable the editor.
    *
-   * @return string Editor's application class name.
+   * @return class-string<PhabricatorApplication> Editor's application
+   *   class name.
    */
   abstract public function getEditorApplicationClass();
 
diff --git a/src/infrastructure/daemon/workers/PhabricatorWorker.php b/src/infrastructure/daemon/workers/PhabricatorWorker.php
index e187623e13..955dac094b 100644
--- a/src/infrastructure/daemon/workers/PhabricatorWorker.php
+++ b/src/infrastructure/daemon/workers/PhabricatorWorker.php
@@ -89,6 +89,9 @@ abstract class PhabricatorWorker extends Phobject {
     return $this;
   }
 
+  /**
+   * @return PhabricatorWorkerTask
+   */
   public function getCurrentWorkerTask() {
     return $this->currentWorkerTask;
   }
@@ -101,6 +104,13 @@ abstract class PhabricatorWorker extends Phobject {
     return $task->getID();
   }
 
+  /**
+   *  Perform some preparations and set up context, then call the final
+   *  functionality (e.g. publishFeedStory() or importEvents() or whatever
+   *  work the PhabricatorWorker subclass is supposed to do).
+   *
+   *  @return void
+   */
   abstract protected function doWork();
 
   final public function __construct($data) {
@@ -120,6 +130,11 @@ abstract class PhabricatorWorker extends Phobject {
     return idx($data, $key, $default);
   }
 
+  /**
+   *  Public wrapper function which calls the doWork() function
+   *
+   *  @return void
+   */
   final public function executeTask() {
     $this->doWork();
   }