Osm:Wmthelp-rendering.labels/en

The label for each route is "guessed" from the tags in the following order:

1. If a `ref` tag exists, make a text label with the `ref` tag. 2. If a `name` tag exists, derive a reference from that, first by using only upper-case letters and failing that by using the first letters of the name. 3. Give up.