You should not use that at all, its just something I was experimenting with to play around with OData. I may remove that code or I may revisit it at some point but it is not up to date and is not working code and should not be used at this point by anyone.
mojoPortal is not built on Entity Framework nor is it going to change to it as a core architecture at any time, but people are free to use EF or any other OR mapper in their own custom code and features.
My advice regarding customization is don't fork the code, otherwise you will not be able to upgrade. If you need to make customizations to an existing feature the only safe way to do it is to clone it which is a safe way of forking it because you create a new feature that is copied from the original feature but is completely separate so it doesn't depend on the same tables or anything else from the original feature. Then you can customize your cloned copy all you want, but if you just start making changes to existing code without cloning you are making a mistake because you will not be able to upgrade without losing your changes.