Is there documentation for the format of verse references such as 01700101000042?

Question

When I export key terms, the file contains verse references like this:
    <References>
      <Verse>01700101000042</Verse>
    </References>

It's sort of clear what this means...

017 - EST

001 - chapter 1

010 - verse 10

00042 - apparently the position of the word in the verse (though I can't see what the system is)

Is this format documented any place?