As more and more plugins are relying on Zen Cart notifiers to perform their customizations, it can be a developer's debug nightmare if an expected notification isn't present. It's kind of like you're waiting for something to do, but no one's there to say "Go do it".
This simple script traverses a site's DIR_FS_CATALOG directory ... and all contained sub-directories ... searching all .php files for the presence of a ->notify call (i.e. the notification itself). Its output is created in a file named notifier_report_YYYYMMDD_HHMMSS.txt in the site's /logs directory. That file contains a list of all .php files containing a notification, identifying the line number(s) and notifications issued.
Here's a sample of the output:
Start notifier report (v1.1.0), created 2020-04-16 13:54:54
admin/admin_activity.php
line#293: 'NOTIFY_ADMIN_ACTIVITY_LOG_RESET'
C:/xampp/htdocs/testsite\admin\attributes_controller.php
line#421: 'NOTIFY_ATTRIBUTE_CONTROLLER_ADD_PRODUCT_ATTRIBUTES', $products_attributes_id
line#565: 'NOTIFY_ATTRIBUTE_CONTROLLER_UPDATE_PRODUCT_ATTRIBUTE', $attribute_id
line#584: 'NOTIFY_ATTRIBUTE_CONTROLLER_DELETE_ATTRIBUTE', array('attribute_id' => $attribute_id), $attribute_id
line#601: 'NOTIFY_ATTRIBUTE_CONTROLLER_DELETE_ALL', array('pID' => $_POST['products_filter'])
line#615: 'NOTIFY_ATTRIBUTE_CONTROLLER_DELETE_OPTION_NAME_VALUES', array('pID' => $_POST['products_filter'], 'options_id' => $_POST['products_options_id_all'])
Note: This is a developer tool, not a "proper" plugin. There's no language file, no means (although it's open source) to create an entry in the admin's menu.
Installation is simple (there's only one file). Simply copy notifier_report.php to your site's admin directory (where the admin_account.php and admin_activity.php files reside). Admin superusers only will be able to access the script, entering a link similar to www.example.com/myadmin/notifier_report.php in the browser's address. The script will take a while (depending on how many files are in that directory-tree) and will print a message to the screen once complete:
Report created: C:/xampp/htdocs/testsite/logs/notifier_report_20190916_135949.txt.
To create a report in markdown format, simply add a markdown variable to that link, e.g. www.example.com/myadmin/notifier_report.php?markdown. That will produce a markdown-formatted file suitable for inclusion in the Zen Cart documents.