VkIndexType(3) Manual Page

// Provided by VK_VERSION_1_0
typedef enum VkIndexType {
    VK_INDEX_TYPE_UINT16 = 0,
    VK_INDEX_TYPE_UINT32 = 1,
  // Provided by VK_KHR_acceleration_structure
    VK_INDEX_TYPE_NONE_KHR = 1000165000,
  // Provided by VK_EXT_index_type_uint8
    VK_INDEX_TYPE_UINT8_EXT = 1000265000,
  // Provided by VK_NV_ray_tracing
    VK_INDEX_TYPE_NONE_NV = VK_INDEX_TYPE_NONE_KHR,
} VkIndexType;