This affects only the relation names which are, by consensus, not intended for data consumer use. Rather, they are meant for editor disambiguation. Many of these routes had no names, but others used different formats that caused similarly-named routes to appear at wildly different positions in a sorted list, so I am using the format "Missouri Route XX".

79 other supplemental route relations already had this tag which is recommended by osm.wiki/United_States_roads_tagging#Tagging_with_relations_(proposal)

This process was carried out by hand.

This was done by hand with each shield addition checked manually.

This was done by hand with each shield addition checked manually.

This was done by hand with each shield addition checked manually.

This was done by hand with each shield addition checked manually.

This was done by hand with each shield addition checked manually.

This was done by hand with each shield addition checked manually.

This was done by hand with each shield addition checked manually.

This was done by hand with each addition checked manually.

This was done by hand with each addition checked manually.

This was done by hand with each addition checked manually.

This was done by hand with each addition checked manually.

This was done by hand with each addition checked manually.

This was done by hand with each addition checked manually.

This was done by hand with each addition checked manually.

In this changeset I also added two communication towers/masts (tagged as masts since they're the "small" lattice type).

As a personal rule, but only in Missouri, I remove name="State Highway XX" tags from ways that are also tagged ref="MO XX" and/or that belong to relations tagged network="US:MO*" && ref=XX. This represents the Missouri state highway tagging consensus as wiki'd.

Also, again, let's not name the road "State Highway HH" when ref tags and route relations exist. This is a fragile, non-machine-readable practice.