bug#36992: linux-libre-5.2.7 failed to build on armhf and aarch64; why?

[Mark H Weaver]

linux-libre-5.2.7 failed to build on Berlin due to a dependency failure:

  https://ci.guix.gnu.org/search?query=linux-libre-5
  https://ci.guix.gnu.org/build/1556871/details
  https://ci.guix.gnu.org/build/1556831/details

I guess that the deblobbing derivation probably failed, but I don't see
a way to confirm this, or to find out what specifically went wrong.

Specifically, I'd like to know:

(1) Which derivations failed, that caused these dependency failures?
(2) Were the failed build logs saved, and if so, how can I see them?
(3) Did the failed derivations time out, or was it another kind of failure?

Can someone help me find out what's going on here?

     Thanks,
       Mark