unlocks are typically by item, but upgrades can be done via tags. In A20, if you had CraftingTier in the Deep Cuts perk, you had the tag perkDeepCuts for the base increase on Quality level. Anything in the items file that had quality levels and the perkDeepCuts in the tags would fall in that group.
From A20
<perk name="perkDeepCuts" parent="skillAgilityCombat" name_key="perkDeepCutsName" desc_key="perkDeepCutsDesc" icon="ui_game_symbol_deep_cuts"> <effect_group> <passive_effect name="CraftingTier" operation="base_add" level="1,2,3,4,5" value="1,2,3,4,4" tags="perkDeepCuts"/> <passive_effect name="RecipeTagUnlocked" operation="base_set" level="1,5" value="1" tags="meleeWpnBladeT1HuntingKnife"/>