MDL-72041 qformat: Remove WebCT question format

WebCT was acquired by Blackboard in 2006, so qformat_webct has been
completely removed from Moodle core.

lib/classes/plugin_manager.php

@@ -1725,6 +1725,7 @@ public static function is_deleted_standard_plugin($type, $name) {
             'block' => array('course_overview', 'messages', 'community', 'participants'),
             'cachestore' => array('memcache'),
             'enrol' => array('authorize'),
+            'qformat' => array('webct'),
             'quizaccess' => array('safebrowser'),
             'report' => array('search'),
             'repository' => array('alfresco'),
@@ -1958,7 +1959,7 @@ public static function standard_plugins_list($type) {
 
             'qformat' => array(
                 'aiken', 'blackboard_six', 'examview', 'gift',
-                'missingword', 'multianswer', 'webct',
+                'missingword', 'multianswer',
                 'xhtml', 'xml'
             ),
 

lib/db/upgrade.php

@@ -2707,5 +2707,15 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2021072800.01);
     }
 
+    if ($oldversion < 2021090200.01) {
+        // Remove qformat_webct (unless it has manually been added back).
+        if (!file_exists($CFG->dirroot . '/question/format/webct/format.php')) {
+            unset_all_config_for_plugin('qformat_webct');
+        }
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2021090200.01);
+    }
+
     return true;
 }

question/format/upgrade.txt

@@ -1,5 +1,10 @@
 This files describes API changes for question import/export format plugins.
 
+=== 4.0 ===
+
+* The WebCT question format has been completely removed (WebCT was acquired by Blackboard in 2006).
+
+
 === 3.6 ===
 
 * Saving question category descriptions (info) is now supported in Moodle XML import/export format.