Use the recommended OSM Tile Server URL scheme #317
Description
TL;DR: Please use https://tile.openstreetmap.org/{z}/{x}/{y}.png - no subdomains and no short names. For more details, see the related issue
Historically, the use of subdomains (i.e. a.tile.openstreetmap.org) or shortened domain names for the tile server URLs (i.e. b.tile.osm.org) has been a standard practice.
However, since the modernised OpenStreetMap Tile server supports HTTP/2 and HTTP/3, the old a|b|c aliases are no longer needed to increase browser connection concurrency.
Besides, using single hostname improves cache efficiency and reduces operational complexity. That's why, the new preferred URL scheme for the OSM Tiles is now https://tile.openstreetmap.org/{z}/{x}/{y}.png. The old URLs add maintenance burden and may stop working in the future.
I will create a PR for this recommended change.