The go command lists all packages that were built.
A recent breakage notification included this text:
$ tail -100 < log
ok errors
ok exp/ebnf
? exp/ebnflint [no test files]
ok exp/gotype
ok exp/norm
ok exp/spdy
If the breakage occurred before this point it would
not be visible in the output.
R=golang-dev, gri, kevlar
CC=golang-dev
https://golang.org/cl/5504109