I think this is an attempt to try to enrich the locality model in transformers.

One of the weird things you do in transformers is add a position vector which captures the distance between the token being attended to the some other token.

This is obviously not powerful enough to express non-linear relationships - like graph relationships.

This person seems to be experimenting with doing pre-processing of the input token set, to linearly reorder it by some other heuristic that might map more closely to the actual underlying relationship between each token.

Adding the position vector is basic sure, but it's naive to think the model doesn't develop its own positional system bootstrapping on top of the barebones one.