Currently after renaming a user action we can't tie it back to the actual naming rule. But you can use the preview to find this information!
Find the preview at the bottom of the user actions page or on both sub pages for creating either placeholders or user action naming rules.
Simply use the URL visible in the default action name and enter it into the preview filter. The check the attributes such as the identifier there. See screenshot
To improve this process, we are currently working on a browser extension that lets you see all such values/attributes right in your browser and right as you trigger the action in your application. This will cut away all the processing on the server that you would usually need to wait to use the preview and all the required navigating through the UI. We plan to release the extension in Q1 next year. If you are interested in using it earlier (e.g. in a preview) ping me!