Custom Operations Filter
There should be a system-maintained prebuilt filter that shows the "Default" Custom operations. This filter cannot be changed or deleted by any user and is "system" maintained. Meaning, only Flexxible devs can update that filter as Default Custom operations are added or removed.
https://docs.flexxible.com/default-custom-operations
If our documentation shows the Default Custom operations, then an admin should be able to filter on that to see the built-in (prebuilt) defaults.