This is not exhaustive technical documentation for every aspect of the installer
code, but it's better than what we had, and it does contain the ping
documentation that this bug was originally asking for.
MozReview-Commit-ID: 5h7UwnAk4Iq
--HG--
extra : rebase_source : a3a8a8bdee9e76ee039c342a07a121170872708c
