Cheetah is an open source template engine and code generation tool.
yelp_cheetah is cheetah with everything we don't / shouldn't use removed.
We really recommend that you don't choose cheetah for new projects, and certainly not this hacked fork. If you're already using cheetah in a legacy project though, you might(?) find this useful.
For a high-level introduction to Cheetah please refer to the User's Guide at http://cheetahtemplate.org/learn.html
TBD