After resolution of ZBXNEXT-4165 "Media types list" Zabbix will have complete list of actions in "Used in actions" column.
Unfortunately it is not enough to identify which media types are actually used. User media type configuration might be missing or disabled.
Also mass delete error message could be improved to indicate which particular media type is linked to which action and thus informing user that media type is actively used.

Use case:

• As a user I want to see which media types are fully configured and actually used.

• As a user I want to be informed on particular media type usage when deleting the media type.