The MediaWiki Developer Summit is an invitation-only event with an emphasis on the evolution of the MediaWiki architecture and the Wikimedia Engineering goals for 2015.
It took place on Monday, January 26 and Tuesday, January 27, 2015 in the Mission Bay Center, San Francisco, California.
Overall it was very interesting and a lot of good discussion happened. Again I am writing this post months after the event so sorry for the lack of content.
Parts of the schedule that I attended