Revamped category sorting
Category sorting has been revamped on English Wikipedia. Titles are now sorted according to the Unicode collation algorithm (phabricator task). The most noticeable change is that characters which differ only in diacritics are now sorted together. Also, numeric sorting is now supported, closing a 10-year-old bug. This should, in many cases, alleviate the need for custom keys to be defined using the DEFAULTSORT behavior switch.
It took approximately a week to regenerate all of the sort keys for English Wikipedia. During this time (29 August to 6 September), sorting in categories was unreliable, prompting reports and discussion in several threads on the technical Village Pump (now archived). One remaining issue is that hyphens are now sorted before commas. This means that hyphenated surnames are sorted earlier if articles use DEFAULTSORT keys of the form "Surname, First name". For example, sorting Jessica Ennis-Hill (sort key "Ennis-Hill, Jessica") before Andy Ennis (sort key "Ennis, Andy"). The issue is being investigated. One proposed solution is to switch to using "Surname First name" in DEFAULTSORT keys.
Improvements to category sorting were one of the projects worked on by the WMF's Community Tech team. The "Numerical sorting in categories" proposal was ranked #5 on the 2015 Community Wishlist Survey, having received 85 support votes. The new collation has also been deployed to Swedish Wikipedia, and may be rolled out to other wikis which agree to switch to the new sorting system.
See how template parameters are used
The Template Parameters tool is now available on Tool Labs, for viewing template parameter usage. It works with TemplateData to show the validity of parameter names that are used in template transclusions. For a required parameter, it can display a list of pages where the template is missing the parameter. The tool also shows commonly used values for each parameter. The data is updated monthly.
As an example, the parameter usage for Template:Multicol is as follows (as of 1 September):