Quoth bug 40207 comment 7:
Open points for future improvement are:
1: tracking history (using history.pushState or hash fragment tracking).
2: mw.hook notifying about finishing the loading of the page fragment
3: using api to do all of it, instead of downloading a full page.
Version: 1.22.0
Severity: enhancement
Whiteboard: gci2013
URL: https://commons.wikimedia.org/wiki/File:MediaWikiPerformanceProfiling.pdf