--8<---------------cut here---------------start------------->8---
$ guix challenge boost
updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
/gnu/store/g70195d256g0nllq75r6zphdf38d9zmr-boost-1.60.0 contents differ:
  local hash: 1ryh34vdsqdd1cjssy5c0sxdf0d2z59blk6jgns395kfq2wgasck
  https://hydra.gnu.org/nar/g70195d256g0nllq75r6zphdf38d9zmr-boost-1.60.0: 1k9xn4wkbl87lfqqmlw66p53nrig506aizxp174l7zla7wlvqx5z
$ wget -q -O - https://mirror.hydra.gnu.org/nar/g70195d256g0nllq75r6zphdf38d9zmr-boost-1.60.0 | bunzip2 | guix archive -x /tmp/boost
$ diff -ur --no-dereference /tmp/boost /gnu/store/g70195d256g0nllq75r6zphdf38d9zmr-boost-1.60.0
Binary files /tmp/boost/lib/libboost_container.so.1.60.0 and /gnu/store/g70195d256g0nllq75r6zphdf38d9zmr-boost-1.60.0/lib/libboost_container.so.1.60.0 differ
$ diffoscope --html t.html /tmp/boost/lib/libboost_container.so.1.60.0 /gnu/store/g70195d256g0nllq75r6zphdf38d9zmr-boost-1.60.0/lib/libboost_container.so.1.60.0
--8<---------------cut here---------------end--------------->8---

Attached the output of diffoscope.

Ludo'.