Marvins is basic framework to works with Crawlers/Parsers, normally when do you have some projects that needs fetch data from some website/api, you have to create one basic structure where you requests some data, parsers this given data and after that you must perists this data in somewhere.
This task is quite frequently and when you have several differents resources to fetch the data it's complicate a bit the structure that you have to define.
Marvins aims to help you in this direction, it define one basic structure to you follow to create your parsers of data, it works using events and fork of process in PHP, that gives more flexibility for you.
It makes usage of Symfony Console, given to you some command line tools to you execute your crawlers.
Marvins is currently on development, and there is no stable version yet.