What is slots value "kind" for?

In hermes/nlu/intentParsed there is a value kind

"entity" : "OnOffValue",
"value" : {
  "kind" : "Unknown",
  "value" : "an"

Is this used for something? Or planned to do so?

In addition to the above question:
Even more interesting would be if there’s any option to fill the “kind” with additional info, I’ve especially the type of the switched device in mind, as reaction in home automation may vary if it’s media type or simple on/off switch (ok, this might be available on the home automation system as well, but perhaps with a higher level of incertanty). Is there any possibilitiy to configure these values? Until now, I’ve only seen “Unknown” as value to the “kind” key, but if there’s no option to change that, the key itself would beobsolete.
So any hint would be appreciated where to find further info.