anchor.diff:              FI => [fi]
               FO => [fo]
               FR => [fr]
  -            FX => [fx]
               GB => [gb]
               GG => [gg]
               GI => [gi]
  
positive.code:           fm => fm.tile.openstreetmap.org.
            fo => fo.tile.openstreetmap.org.
            fr => fr.tile.openstreetmap.org.
            fx => fx.tile.openstreetmap.org.
            ga => ga.tile.openstreetmap.org.
            gb => gb.tile.openstreetmap.org.
            gd => gd.tile.openstreetmap.org.
  
negative.code:           NA => {
              AG => [ag]
              AI => [ai]
              AW => [aw]
              BB => [bb]
              BL => [bl]
  