Flux architecture in php

Of all the articles I have read and tutorials I have seen on Facebook's Flux architecture, They all are demonstrated using Nodejs Backend and front-end is commonly reactJS ( I have read one with angularJS too ). But they all are focused on Front-End perspective.

Strictly from backend perspective, How do I structure my project code according to Flux Architecture? To be clear, MVC design pattern is actually clear on how the files should be arranged, frameworks have their own implementation but still are clear on how project is to be arranged, and organized. What should be the backend structure of a project according to Flux Architecture? Are there any open source framework for Flux architecture, like codeignighter is for MVC?

I was never a fan of MVC, and ever since I discovered Micro-frameworks, I have used my own version of Modal-View design pattern (surprisingly similar to a stripped down Flux pattern). But I have always been hazy on how I should structure it.

Facebook's post on Flux pattern explains a lot about speed and security. But all the tutorials focus only on ReactJS. Tutorials from Pluralsight, egghead and everything else I have come across past year, uses a NodeJS backend. 99% of them don't really demonstrate flux architecture, but shows working with ReactJS. So After almost year long of searching, I am still unclear on what flux exactly is.