How to use a code
Your own loot filter matches items by their code: code: uap matches every Shako. A unique or set item uses its base item's code, so add quality: unique to match only the unique one, the way the standard rules announce Harlequin Crest. The Guide button in the launcher's Loot filter window has the same list, made from your installed mod.
In testing Names instead of codes: a rule's code: line takes item names as well as codes, in English or German and in any case, so code: Shako "Harlequin Crest" Ber r31 works. Put a name with spaces in quotes when it sits next to other names. A unique or set item's name means its base item as a unique or set item: Harlequin Crest is a unique Shako, which is all the game knows before you identify it. In a rule that sets name, sound or pillar, use base item names, since those belong to the base item.
All item codes
The full list fills in with the next release.