Steps to reproduce the issue

Created a Privacy -> Create Request menu item in the frontend and completed the workflow:

• Accessed the menu in front end
• Logged in with user data I want to delete
• Selected Delete as request type
• Clicked the URL in the request email
• Completed the token form

Then accessed Users->Privacy->Requests in the backend and clicked the red cross button in the actions column which triggers request.remove

Expected result

User data anonymized

Actual result

Used data kept intact

System information (as much as possible)

Joomla 4.4.1 PHP 7.4

Additional comments

I can see that onPrivacyCanRemoveData and onPrivacyRemoveData member functions don't get hit.

If I rename plugins/privacy/user/src/Extension/UserPlugin.php to plugins/privacy/user/src/Extension/User.php and do proper changed in the class, like, renaming the class name to User and some other changes that I attached to this bug report, the plugin works, and the data gets anonymized

<?php

/**
 * @package     Joomla.Plugin
 * @subpackage  Privacy.user
 *
 * @copyright   (C) 2018 Open Source Matters, Inc. <https://www.joomla.org>
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

namespace Joomla\Plugin\Privacy\User\Extension;

use Joomla\CMS\Language\Text;
use Joomla\CMS\Table\User as TableUser;
use Joomla\CMS\User\User as UserObject;
use Joomla\CMS\User\UserHelper;
use Joomla\Component\Privacy\Administrator\Plugin\PrivacyPlugin;
use Joomla\Component\Privacy\Administrator\Removal\Status;
use Joomla\Component\Privacy\Administrator\Table\RequestTable;
use Joomla\Database\ParameterType;
use Joomla\Event\SubscriberInterface;
use Joomla\Utilities\ArrayHelper;

// phpcs:disable PSR1.Files.SideEffects
\defined('_JEXEC') or die;
// phpcs:enable PSR1.Files.SideEffects

/**
 * Privacy plugin managing Joomla user data
 *
 * @since  3.9.0
 */
final class User extends PrivacyPlugin
{
    /**
     * Performs validation to determine if the data associated with a remove information request can be processed
     *
     * This event will not allow a super user account to be removed
     *
     * @param   RequestTable  $request  The request record being processed
     * @param   User          $user     The user account associated with this request if available
     *
     * @return  Status
     *
     * @since   3.9.0
     */
    public function onPrivacyCanRemoveData(RequestTable $request, UserObject $user = null)
    {
        $status = new Status();

        if (!$user) {
            return $status;
        }

        if ($user->authorise('core.admin')) {
            $status->canRemove = false;
            $status->reason    = Text::_('PLG_PRIVACY_USER_ERROR_CANNOT_REMOVE_SUPER_USER');
        }

        return $status;
    }

    /**
     * Processes an export request for Joomla core user data
     *
     * This event will collect data for the following core tables:
     *
     * - #__users (excluding the password, otpKey, and otep columns)
     * - #__user_notes
     * - #__user_profiles
     * - User custom fields
     *
     * @param   RequestTable  $request  The request record being processed
     * @param   User          $user     The user account associated with this request if available
     *
     * @return  \Joomla\Component\Privacy\Administrator\Export\Domain[]
     *
     * @since   3.9.0
     */
    public function onPrivacyExportRequest(RequestTable $request, UserObject $user = null)
    {
        if (!$user) {
            return [];
        }

        /** @var TableUser $userTable */
        $userTable = UserObject::getTable();
        $userTable->load($user->id);

        $domains   = [];
        $domains[] = $this->createUserDomain($userTable);
        $domains[] = $this->createNotesDomain($userTable);
        $domains[] = $this->createProfileDomain($userTable);
        $domains[] = $this->createCustomFieldsDomain('com_users.user', [$userTable]);

        return $domains;
    }

    /**
     * Removes the data associated with a remove information request
     *
     * This event will pseudoanonymise the user account
     *
     * @param   RequestTable  $request  The request record being processed
     * @param   User          $user     The user account associated with this request if available
     *
     * @return  void
     *
     * @since   3.9.0
     */
    public function onPrivacyRemoveData(RequestTable $request, UserObject $user = null)
    {
        // This plugin only processes data for registered user accounts
        if (!$user) {
            return;
        }

        $pseudoanonymisedData = [
            'name'     => 'User ID ' . $user->id,
            'username' => bin2hex(random_bytes(12)),
            'email'    => 'UserID' . $user->id . 'removed@email.invalid',
            'block'    => true,
        ];

        $user->bind($pseudoanonymisedData);

        $user->save();

        // Destroy all sessions for the user account
        UserHelper::destroyUserSessions($user->id);
    }

    /**
     * Create the domain for the user notes data
     *
     * @param   TableUser  $user  The TableUser object to process
     *
     * @return  \Joomla\Component\Privacy\Administrator\Export\Domain
     *
     * @since   3.9.0
     */
    private function createNotesDomain(TableUser $user)
    {
        $domain = $this->createDomain('user_notes', 'joomla_user_notes_data');
        $db     = $this->getDatabase();

        $query = $db->getQuery(true)
            ->select('*')
            ->from($db->quoteName('#__user_notes'))
            ->where($db->quoteName('user_id') . ' = :userid')
            ->bind(':userid', $user->id, ParameterType::INTEGER);

        $items = $db->setQuery($query)->loadAssocList();

        // Remove user ID columns
        foreach (['user_id', 'created_user_id', 'modified_user_id'] as $column) {
            $items = ArrayHelper::dropColumn($items, $column);
        }

        foreach ($items as $item) {
            $domain->addItem($this->createItemFromArray($item, $item['id']));
        }

        return $domain;
    }

    /**
     * Create the domain for the user profile data
     *
     * @param   TableUser  $user  The TableUser object to process
     *
     * @return  \Joomla\Component\Privacy\Administrator\Export\Domain
     *
     * @since   3.9.0
     */
    private function createProfileDomain(TableUser $user)
    {
        $domain = $this->createDomain('user_profile', 'joomla_user_profile_data');
        $db     = $this->getDatabase();

        $query = $db->getQuery(true)
            ->select('*')
            ->from($db->quoteName('#__user_profiles'))
            ->where($db->quoteName('user_id') . ' = :userid')
            ->order($db->quoteName('ordering') . ' ASC')
            ->bind(':userid', $user->id, ParameterType::INTEGER);

        $items = $db->setQuery($query)->loadAssocList();

        foreach ($items as $item) {
            $domain->addItem($this->createItemFromArray($item));
        }

        return $domain;
    }

    /**
     * Create the domain for the user record
     *
     * @param   TableUser  $user  The TableUser object to process
     *
     * @return  \Joomla\Component\Privacy\Administrator\Export\Domain
     *
     * @since   3.9.0
     */
    private function createUserDomain(TableUser $user)
    {
        $domain = $this->createDomain('users', 'joomla_users_data');
        $domain->addItem($this->createItemForUserTable($user));

        return $domain;
    }

    /**
     * Create an item object for a TableUser object
     *
     * @param   TableUser  $user  The TableUser object to convert
     *
     * @return  \Joomla\Component\Privacy\Administrator\Export\Item
     *
     * @since   3.9.0
     */
    private function createItemForUserTable(TableUser $user)
    {
        $data    = [];
        $exclude = ['password', 'otpKey', 'otep'];

        foreach (array_keys($user->getFields()) as $fieldName) {
            if (!in_array($fieldName, $exclude)) {
                $data[$fieldName] = $user->$fieldName;
            }
        }

        return $this->createItemFromArray($data, $user->id);
    }
}