This folder contains all sniffs which we (re)implemented to match the TYPO3 Coding Guidelines. We call it the SniffPool.
Since this standard is a dependency of TYPO3CMS and TYPO3Flow standard, you don't need to install this standard directly. It will automatically installed when you install one of the mentioned standards.
Since it is an own standard it is possible to call it. This is not recommended! It will raise weird errors.
We provide separate standards who match the coding guidelines of TYPO3CMS and TYPO3Flow.