provenance/payneheirs_getty/2 matches the site

public static Activity Purchase_With_Custody_To_Department()
{
    var purchase = new Activity()
        .WithContext()
        .WithId("https://linked.art/example/provenance/payneheirs_getty/2")
        .WithLabel("Purchase of Spring")
        .WithClassifiedAs(Aat.ProvenanceActivity);

    var spring = new HumanMadeObject()
        .WithId("https://linked.art/example/object/spring")
        .WithLabel("Spring");
    var payneHeirs = new Group()
        .WithId("https://linked.art/example/group/payne_heirs")
        .WithLabel("Family of Oliver Payne");

    purchase.Part = [
        new Acquisition
        {
            Label = "Acquisition of Painting",
            TransferredTitleOf = [spring],
            TransferredTitleFrom = [payneHeirs],
            TransferredTitleTo = [
                new Group()
                    .WithId("https://linked.art/example/group/getty")
                    .WithLabel("J. Paul Getty Museum")
            ]
        },
        new TransferOfCustody
        {
            Label = "Custody by Department",
            TransferredCustodyOf = [spring],
            TransferredCustodyFrom = [payneHeirs],
            TransferredCustodyTo = [
                new Group()
                    .WithId("https://linked.art/example/group/getty_ptgs")
                    .WithLabel("Paintings Department")
            ]
        }
    ];

    return purchase;
}

var activity = new Activity
{
    Context = ["https://linked.art/ns/v1/linked-art.json"],
    Id = "https://linked.art/example/provenance/payneheirs_getty/2",
    Label = "Purchase of Spring",
    ClassifiedAs = [Aat.ProvenanceActivity],
    Part =
    [
        new Acquisition
        {
            Label = "Acquisition of Painting",
            TransferredTitleOf =
            [
                new HumanMadeObject
                {
                    Id = "https://linked.art/example/object/spring",
                    Label = "Spring",
                },
            ],
            TransferredTitleFrom =
            [
                new Group
                {
                    Id = "https://linked.art/example/group/payne_heirs",
                    Label = "Family of Oliver Payne",
                },
            ],
            TransferredTitleTo =
            [
                new Group
                {
                    Id = "https://linked.art/example/group/getty",
                    Label = "J. Paul Getty Museum",
                },
            ],
        },
        new TransferOfCustody
        {
            Label = "Custody by Department",
            TransferredCustodyOf =
            [
                new HumanMadeObject
                {
                    Id = "https://linked.art/example/object/spring",
                    Label = "Spring",
                },
            ],
            TransferredCustodyFrom =
            [
                new Group
                {
                    Id = "https://linked.art/example/group/payne_heirs",
                    Label = "Family of Oliver Payne",
                },
            ],
            TransferredCustodyTo =
            [
                new Group
                {
                    Id = "https://linked.art/example/group/getty_ptgs",
                    Label = "Paintings Department",
                },
            ],
        },
    ],
};

Generated from the object the example builds: every property that is set, as object initialisers, with the vocabulary constants where a term is in the registry. The fluent helpers are a convenience, not a requirement; this form and the one as written produce the same JSON.