Thanks to RobLa for posting this, I would not have been aware of it. Thanks to Brion for bringing the subject up.
I've been made aware of this summit by a post on the MediaWiki-Distributors mailling list. I'm interested in participating but uncertain as my involvement in MediaWiki related things are low. A few years ago, I did dip my toe into some dev efforts surrunding MSSQL, LDAP and SemanticMediawiki. I got access to gerrit as well as the WMFlabs infrastructure and was able to propose a few patch and work in bugzilla. It just a little before the big switch to Phabricator. That change to Phabricator and all the changes surrounding it got the better of me and I gave up at that time. Today still, I'm struggling with new development efforts introduced after that switch (Composer, Lua and others) and keep myself on the LTS.
In any case, here is some suggestion of topics you could discuss (keep in mind, it's only suggestion and I've been out of the loop since a while).
- Difficulties of integration of MediaWiki Core, Semantic MediaWiki and WikiData. WMF is not using Semantic MediaWiki and focus mostly on WikiData. Although a lot of effort is made by peoples behind Semantic MediaWiki, I find still find it hard today to figures the where and what when you try to mix it all together. All by themself the blocks are well documented and easy to find, it's mixing it up that it. Why has Semantic not been adopted more broadly? What is the main difference between SemanticMediaWiki and WikiData? Was there too much effort duplicated?
- Recently there has been some developpment around Microsoft SQL support. Microsoft and others has shown a lot of interest and put a lot of effort into pushing the MSSQL Database implementation. I do have some interest into and I believes peoples are forgeting an very viable and forgotten alternative that is FreeTDS and Extension:MSSQLBackCompat. How can MSSQL support be brough into the mix while keeping the later able to run? And why is effor on MSSQL on Windows take so much place while MSSQL on Linux (thought FreeTDS) is pushed away? The main Databases classes are for heavy use and have a lot of code, is there a way to have a faster, easier and dummer Database class that would bring content into the wikitext and not have to worry with the whole compatibility with the main one?
- Speaking of Database, my feeling is peoples seem unaware of using two Databases drivers at the same time, yet that is a fantastic feature and I use in my own private instance to fetch data from outside the wiki tables. For example, my main Database driver is MySQL like almost everyone yet my MediaWiki instance does run query into some MSSQL Database through the previously mentionned extension.
- Speaking of content brought in from external source, I know there is a lot of talk this year about something else than text/plain or text/wikitext. What about pulling data from entreprise dashboard, external event, bus system, other database and what not? What could be done in the back end to bring more datasource to the rendering and parsing engine? What about pushing it back? What about readonly backend while the wikitext remain readwrite?
- Regarding developpement tools and WMF processes. Lately the foundation have got a lot of new toys and improvement around the developpement process. Those involved in those processes on a daily or weekly process can follows it with some easy but, in 2012, I felt the bar to contribute was quite high. Today, as a casual hacker, I don't see the bar anymore and I'm overwhelm with resuming any work within the source code.
- As a Debian user, the packaged version of MediaWiki is 1.19 and therefore it is still part of my work to work against the 1.19 code base. As you can imagine this is very hard to approch the new concept while still being dragged by use way of working from 1.19 era. What could be done to help package or be packge friendly? Why caused such a lag behind? There is bring new on this issue though, the lastest and newest is starting to appear on Debian due to some amazing work from many developers that tackle that issue and I'm looking forward to Debian 'Stretch' with MediaWiki 1.27!
- My use case of MediaWiki is behind a private firewall and therefore face some different challenge than WikiMedia. I believes most devs are familiars with those use cases as there was many presentation in years piors about use of the MediaWiki software elsewhere. But what is the future for them? Is there a middle ground between the CIA super isolated MediaWiki and the public non-WikiMedia MediaWiki server that use and consume contents from Commons and WikiData? What about two private users sharing between each others insteads? A 'Common' outside Commons and the public web but still sharable between two instances? What about sharing Template? Pulling the amazeball templates from Wikipedia and pulling it it? What about a better starting wikitext database with those fancy things peoples think for granted in Wikipedia but is not so easy to build from scratch? Available so close, right at your finger tips but it's breaking like choas so easily in your private instead?
Thanks you to all the devs for this amazing software even though my tone might have not appear cheerful in the previous comments, rest assured that MediaWiki's code base still amaze me everything I look at it. It's a fantastic endeavour and I'm very grateful for everyone's contribution to it. I'm cheering for your success! (sorry for my bad English, it's not my native language)