Some series have volume extras that get inserted far away from the current latest non-volume chapter, or earlier chapters get redone/fixed. Being able to sort the chapters by clicking the clock icon on the series page would help surface these.
OpenSearch is a method to let browsers search the site without having to load the front page first. It's implemented by just adding an XML template and a markup tag pointing to it.
By adding it, supporting browsers can automatically detect and add support. Users can then type something like...