[ 200 Service home ]
+ [ 210 Credentials ]
+ [ 211 Username ]
+ [ 212 Password ]
+ [ 213 API Key ]
+ [ 214 --> Join ]
+ [ 215 --> documentation ]
+ [ 220 Accept-Language ]
Example language codes or make up your own!
+ [ 221 MRU list (maybe later) ]
+ [ 222 Whole list ]
source