If set, will be equal to "1", and indicates HTTPS protocol. This value could be set for all mobile traffic and not just Zero (and hopefully one day - on all desktop traffic too)
This is obviously outdated considering that we have been switching everything to HTTPS since 2015.
What is the current meaning of the field? It is not always set to "1" now:
SELECT x_analytics_map['https'] AS https_value, COUNT(*) AS requests FROM wmf.webrequest WHERE month = 3 AND day = 2 GROUP BY x_analytics_map['https']; https_value requests NULL 350167351 1 7859037939 2 rows selected (232.636 seconds)
Can one assume that the NULL values correspond to HTTP requests? (I understand that such requests, say for http://en.wikipedia.org/wiki/Main_Page , are nowadays always answered with a 301 redirect to the corresponding HTTPS URL.)