abilityActivationTypes_unchained: {
    action: "Action";
    aoo: "Attack of Opportunity";
    attack: "Attack";
    free: "Free";
    hour: "Hour";
    minute: "Minute";
    nonaction: "Nonaction";
    passive: "Passive";
    reaction: "Reaction";
    special: "Special";
} = ...

This describes the ways that an ability can be activated when using Unchained rules.