53219 is a postalcode and its consensus geometry is derived from uszcta.
{"mz:is_ceased":0,"geom:latitude":42.995497,"wof:name":"53219","counts:names_total":0,"wof:placetype":"postalcode","mz:is_current":1,"wof:hierarchy":[{"continent_id":102191575,"country_id":85633793,"county_id":102081837,"localadmin_id":404492091,"locality_id":101732987,"postalcode_id":554727689,"region_id":85688517}],"mz:is_deprecated":0,"lbl:latitude":42.995181,"mz:postal_locality_alt":["West Allis"],"geom:area":0.001416,"geom:longitude":-87.99226,"wof:id":554727689,"counts:concordances_total":1,"geom:type":"Polygon","wof:lastmodified":1611185500,"wof:belongsto":[102191575,85633793,102081837,404492091,101732987,85688517],"wof:concordances":{"gp:id":"12780917"},"wof:repo":"whosonfirst-data-postalcode-us","src:geom":"uszcta","wof:country":"US","counts:names_preferred":0,"geom:area_square_m":1.2806951545534E7,"wof:tags":[],"counts:names_variant":0,"wof:breaches":[],"edtf:inception":"uuuu","iso:country":"US","counts:names_languages":0,"geom:bbox":"-88.017693,42.981013,-87.958583,43.012352","wof:superseded_by":[],"wof:supersedes":[],"lbl:longitude":-87.993688,"wof:geomhash":"ea06616bfbb9a750f1757757540ff7be","wof:parent_id":101732987,"wof:placetype_names":["postalcode"],"mz:hierarchy_label":1,"wof:placetype_id":470996387,"edtf:cessation":"uuuu","mz:postal_locality":"Milwaukee"}