Stored in extra. Depending on the flags in Data, there will be up to 5 trailing Ref fields:
has_sentinel flag is sethas_align flag is sethas_addrspace flag is sethas_bit_range flag is sethas_bit_range flag is setelem_type: Refsrc_node: i32pub const PtrType = struct {
elem_type: Ref,
src_node: i32,
}