AF3 Ambiguity

So... this has been bothering me for quite awhile now but... I have no idea what the "Enhances Feather Step" On my Charis Toe-Shoes +1 do, let alone how it can be further enhanced via +2. From testing on other sites, it doesn't seem to have any affect on further increasing crit rate or crit damage and its been a few months and nobody seems to know what this mystery enhancement does. I would really like to know exactly what it is I improved.

Are there any other pieces of AF3 that have enhancements that people haven't been able to figure out? Most of the enhancements have already been figured out, but have there been any others that have slipped through the cracks that people would like either the community to compile information on, or have the dev team reveal what it is they do?