oUF is a unit frame framework.
It attempts to simplify the process of writing unit frames for WoW by doing all the trivial and painfully boring parts for you, so you can focus more on experimenting with the look of the frames.
By itself oUF doesn't do much, a layout is required.
All the documentation can be found in the source code (until we publish it online).
If you're upgrading to version 10.0, see our upgrade guide.
If you intend to embed oUF into your project, please refer to our embedding wiki page.
Please search first to make sure your issue has not been reported/solved already.
Generally, bugs should be reported through the author of the layout you're using.