How does MTR learn MPLS labels on distant hops?

When running MTR towards a remote site's IP, I was surprised to see the ISP MPLS labels in the output.

How does my machine know these labels given that the first (local) MPLS router is a few hops away from me? I assumed the labels should be stripped off there.

Tip: In Linux, if your MTR doesn't show these labels, press "e" while the trace is running.

Edit: Cool, there's a web-based, Internet version here: http://mtr.guru/?www.airkoryo.com.kp