Templat:Navbox visibility
Templates using the classes class=navbox
({{navbox}}) or class=nomobile
({{sidebar}}) are not displayed on the mobile web site of English Wikipedia. Mobile page views account for approximately 68% of all page views (90-day average Templat:As of). Briefly, these templates are not included because 1) they are not well designed for mobile, and 2) they significantly increase page sizes—bad for mobile downloads—in a way that is not useful for the mobile use case. You can review/watch phab:T124168 for further discussion.
[create] Template documentation