This table's description was never updated after we changed the field's definition to distinguish between search engines and other domains for external referrers, and to distinguish "none" and "unknown":
$ DESCRIBE wmf.pageview_hourly col_name data_type comment ... referer_class string Can be internal, external or unknown ...
SELECT DISTINCT referer_class FROM wmf.pageview_hourly WHERE year = 2018 AND month = 3 AND day = 22; referer_class unknown internal external (search engine) none external
- - Provide patch in schema definition
- - Update production table and doc.