Adding TreeRowReference (persistent reference to a node in a TreeModel). new_proxy() and related methods are ignored since reordered() can't be auto-generated. However, proxy references are "not generally needed by most applications." (cit. from docs)
IMHO reordered fact that not generated is no reason to ignore it (without comment we just forget about that function and never implement it 😉 ).
Same as for other: while it normally used together with reordered, IMHO there are cases where allowed only insert\remove without reordering and new_proxy can be safely used