The difference between master and develop branches

[ymhuang0808]

Thanks for the great project for processing liquid files in PHP.

There are two branches in the project. It seems like that the develop branch supports unless tag and the directory structure is also different with master branch. Because the unless tag was already implemented in 2015, does the unless tag feature plan to be merged into master branch?

If I would like to contribute the project, which branch should I fork?