55121 is a postalcode and its consensus geometry is derived from uszcta.
{"mz:is_ceased":0,"geom:latitude":44.847064,"wof:name":"55121","counts:names_total":0,"wof:placetype":"postalcode","mz:is_current":1,"wof:hierarchy":[{"continent_id":102191575,"country_id":85633793,"county_id":102087895,"localadmin_id":404512099,"locality_id":85968491,"postalcode_id":554729091,"region_id":85688727}],"mz:is_deprecated":0,"lbl:latitude":44.846541,"mz:postal_locality_alt":["Eagan","St Paul"],"geom:area":0.002884,"geom:longitude":-93.154298,"wof:id":554729091,"counts:concordances_total":1,"geom:type":"Polygon","wof:lastmodified":1611185415,"wof:belongsto":[102191575,85633793,102087895,404512099,85968491,85688727],"wof:concordances":{"gp:id":"12781756"},"wof:repo":"whosonfirst-data-postalcode-us","src:geom":"uszcta","wof:country":"US","counts:names_preferred":0,"geom:area_square_m":2.5283228465835E7,"wof:tags":[],"counts:names_variant":0,"wof:breaches":[],"edtf:inception":"uuuu","iso:country":"US","counts:names_languages":0,"geom:bbox":"-93.20776,44.827909,-93.104812,44.86293","wof:superseded_by":[],"wof:supersedes":[],"lbl:longitude":-93.154935,"wof:geomhash":"3c29950ee332f1d9558e406efea79756","wof:parent_id":85968491,"wof:placetype_names":["postalcode"],"mz:hierarchy_label":1,"wof:placetype_id":470996387,"edtf:cessation":"uuuu","mz:postal_locality":"Saint Paul"}