The new version of Flow using it is in the frontend-rewrite branch.
It has possible features of
floating Table of Contents on the right for navigation and indicating progress on the boarddropped from first sprint
- Agora enhancements (all in local code, some proposed for core)
- revised Agora button styling
- new drop-down menu replaces flyout menu
- new Agora colored tooltip
- Design/WikiFont for symbols
- remembers stat, e.g. user's choice of regular/collapsed/small view of topics on the board.
- new sort by Recent active topics as well as default by Newest topics.
The new front-end uses handlebars.js on the client to render templates supplied by ResourceLoader, and lightncandy in PHP to render the same templates pre-compiled at commit-time. Tracking bug 63443, security review is bug 63445. WMF will likely standardize on a templating library similar to Knockout but the PHP implementation is not ready yet.
See Flow/Architecture/Templating for Flow's approach to handlebars, helper functions, adding JS interactivity, etc.