Namespaced system labels (e.g. gmail:trash, gmail:bin) with one canonical representation which is actually stored in the database, these can be aliased in the b

Namespaced system labels (e.g. gmail:trash, gmail:bin) with one canonical representation which is actually stored in the database, these can be aliased in the backend to all of the localized labels. Custom user labels can be arbitrary, non-namespaced free text using any string except “gmail”.