In the Example policy in policy.md the witness Y2 line is repeated

In the "Example policy" in https://git.glasklar.is/sigsum/core/sigsum-go/-/blob/main/doc/policy.md the "witness Y2 " line is repeated, it looks like this:

witness Y1 <key>
witness Y2 <key>
witness Y2 <key>
group Y-witnesses any Y1 Y2 Y2

Is that intentional and of so, what does it mean? Or is it a typo, the second "Y2" should be "Y3"?