Grav - is a modern open source flat-file CMS
This is CMS developed by RocketTheme and use only html+php , and NO mysql!
fast, speed, ease and open source.
this is a good idea, if you develop your extension for this CMS. probably i'm move from Joomla to Grav at one moment.
We do like Grav. However, we haven't supported any other CMS's with JFBConnect and Grav won't be the first. It's possible we may expand into other CMS's in 2016 as that would be very exciting, and we are working to make our code more compatible with common frameworks, but it's a very big job to port to other systems while keeping the rich feature set and without making support an absolute nightmare.
I'd definitely love to hear your feedback if you start using Grav on how it goes!