And here comes a little preview of what's currently available in the wip/osm-edit branch of gnome-maps.
This shows some actual live updating of OSM data.
A small screencast showing the current state of OpenStreetMap editing in gnome-maps.
Note how pasting a wikipedia link automagically reformats the link to the OSM wikipedia tag format.
Also note how the stored place (the data shown in the popover for the place) is updated after a successful edit.
You still need to supply your OSM username and password via environments variables, as there is no settings UI for this yet.