This came in as a feature request but I moved it to #general because observation fields are made by community members and not something that staff edit.
Annotations are sort of “official” observation fields, and can be discussed here: https://forum.inaturalist.org/t/lets-talk-annotations/627
You can search to see who has created an observation field at this page: https://www.inaturalist.org/observation_fields for example a search for plumage finds this field for plumage season: https://www.inaturalist.org/observation_fields/3527 which indicates @uheise created the field. You can send them a message or leave a comment at the bottom of that page requesting changes to the field.