1. Create LLD rule with Item prototype
2. Wait until item is discovered.
3. Go to Host items list, click on item name -> open discovered item form -> all fields are disabled, there is link to LLD rule above.
4. Click LLD rule's link.
LLD rule's items prototypes list is opened.
Specific item prototype's editable form is opened - similarly to templated item forms.
The same behavior is actual for triggers and graphs created on host from prototype.