XkbLookupKeyBinding is the equivalent of the core XLookupString function.
XRebindKeysym binds an ASCII string to a specified keysym, so that the string and keysym are returned when the key is pressed and a specified list of modifiers are also being held down. XkbLookupKeyBinding returns in buf the string associated with the keysym sym and modifier state state. buf is NULL terminated unless there's an overflow. If the string returned is larger than nbytes, a count of bytes that does not fit into the buffer is returned in extra_rtrn. XkbTranslateKeySym returns the number of bytes that it placed into buf.