What does it do?

To put it simple: kreXX is an alternative for the fluid debugger <f:debug/>.

The problem with <f:debug/> is that is can be a little bit discrete when debugging objects. It only shows protected properties which may or may not be reachable in the template file.

kreXX gives you a good overview about the object and how to reach specific values inside.

<!-- Normal frontend output -->
<krexx:debug>{_all}</krexx:debug>
<!-- Force the logging into a file -->
<krexx:log>{_all}</krexx:log>

You can also use it as a PHP debugger:

// Normal frontend output
krexx($myObject);
// Force the logging into a file
krexxlog($myObject);