https://lists.wikimedia.org/pipermail/analytics/2015-May/003978.html said:
Well, the pageviews data will very deliberately /not/ contain any data from the chapters' wikis.
https://wikitech.wikimedia.org/wiki/Analytics/Pagecounts-all-sites and https://wikitech.wikimedia.org/wiki/Analytics/Data/Pagecounts-raw don't explicitly mention a difference in covered wikis compared to webstatscollector nor a date, but they say that only some wikimedia.org subdomains are included. So, apparently, this change has already happened in pagecounts-raw, possibly starting on 2015-01-01 (switch to Hive).
It's not consistent to include the WMF wiki and exclude chapters wikis, moreover the foundationwiki stats have been completely wrong for a long time (T51266: www.f / foundationwiki (wikimediafoundation.org) pageviews low, underreporting?), hence I propose to remove this domain as well.