Originally this was a complete runtime for using Esoteric Software's Spine with MonoGame - developed because the XNA runtime was not yet available.
However the official XNA runtime is now available! And furthermore there is an official MonoGame runtime. Therefore this repository is much smaller and just contains a demo iOS application.
If you want to run this then you'll need MonoGame (https://github.com/mono/MonoGame) and also the xamarin-ios projects from the Esoteric Software (https://github.com/EsotericSoftware/spine-runtimes)
Have fun :)