That plugin gives external programs the ability to interface with k-meleon. It's used by StrokeIt (new site, http://www.tcbmi.com/strokeit) to give kmeleon mouse gesture support.
btw: if one wants to configure this plugin nothing happens. two possible solutions that i can think of: a) disable the configure-button for this plugin (difficult?) or b) let a message box appear ("plugin can't be configured" or similar).
Yes, that's what makes this cool I'll document it eventually, but if you look at the source in the CVS, its functionality should be pretty straightforward.