This branch is used for development of the VanillaBootstrap theme. As I'm currently working on a version for the 2.1 branch of Vanilla this version is not at all intended for use in a production environment as it's nowhere near being completed. Please refer to https://github.com/kasperisager/VanillaBootstrap/ if you want to download the latest stable build of VanillaBootstrap.
I'm using a rather simple versioning system that looks like this: [major].[minor][state]-[vanilla] where [vanilla] indicates which branch of Vanilla the theme is compatible with.