The package provides facilities for creating and managing keys
in the sense of the keyval and xkeyval packages, but it is
intended to be more robust and faster. Its robustness comes
from its ability to preserve braces in key values throughout
parsing. The need to preserve braces in key values arises often
in parsing keys (for example, in the xwatermark package). The
package is faster than xkeyval package because (among other
things) it avoids character-wise parsing of key values (called
"selective sanitization" by the xkeyval package). The package
also provides functions for defining and managing keys.