20620 is a postalcode and its consensus geometry is derived from uszcta.
{"mz:is_ceased":0,"geom:latitude":38.231588,"wof:name":"20620","counts:names_total":0,"wof:placetype":"postalcode","mz:is_current":1,"wof:hierarchy":[{"continent_id":102191575,"country_id":85633793,"county_id":102082729,"postalcode_id":554706871,"region_id":85688501}],"mz:is_deprecated":0,"lbl:latitude":38.233918,"geom:area":0.001056,"geom:longitude":-76.523304,"wof:id":554706871,"counts:concordances_total":1,"geom:type":"Polygon","wof:lastmodified":1611182708,"wof:belongsto":[102191575,85633793,102082729,85688501],"wof:concordances":{"gp:id":"12766202"},"wof:repo":"whosonfirst-data-postalcode-us","src:geom":"uszcta","wof:country":"US","counts:names_preferred":0,"gp:parent_id":"12588695","geom:area_square_m":1.026043859827E7,"wof:tags":[],"counts:names_variant":0,"wof:breaches":[],"edtf:inception":"uuuu","iso:country":"US","counts:names_languages":0,"geom:bbox":"-76.549695,38.206578,-76.494827,38.254168","wof:superseded_by":[],"wof:supersedes":[],"lbl:longitude":-76.528932,"wof:geomhash":"61a21a104c88407e14d3b1568c247e68","wof:parent_id":102082729,"wof:placetype_names":["postalcode"],"mz:hierarchy_label":1,"wof:placetype_id":470996387,"edtf:cessation":"uuuu","mz:postal_locality":"Callaway"}