Use preferred tile.openstreetmap.org URL

[Firefishy]

TL;DR: Please use https://tile.openstreetmap.org/{z}/{x}/{y}.png - no subdomains and no short names.

Many projects, examples, and documentation still use older URLs for the tile.openstreetmap.org tile service. Please update them as follows:

• a.tile.openstreetmap.org → tile.openstreetmap.org
• b.tile.openstreetmap.org → tile.openstreetmap.org
• c.tile.openstreetmap.org → tile.openstreetmap.org
• a.tile.osm.org → tile.openstreetmap.org
• b.tile.osm.org → tile.openstreetmap.org
• c.tile.osm.org → tile.openstreetmap.org
• tile.osm.org → tile.openstreetmap.org
• http://* → https:// (use HTTPS)

tile.openstreetmap.org supports HTTP/2 and HTTP/3, so the old a|b|c aliases are no longer needed to increase browser connection concurrency. Using a single hostname also improves cache efficiency and reduces operational complexity.

The old URLs add maintenance burden and may stop working in the future. Please switch to the preferred URL now.

(This issue tracks 3rd party projects on GitHub and elsewhere that need updating to the preferred tile.openstreetmap.org URL.)