When the Raptor pageload test is run, the mitmproxy recording archive for use during the test is automatically downloaded from tooltool.
The following process was used to record the mitmproxy page archives (on OSXmacOS):
1. Install Mitmproxy 2.X following the mitmproxy [http://docs.mitmproxy.org/en/stable/install.html installation instructions]. We use version 2.0.2 in production (and that was the version used to record the current pagesets). Note that we are unable to upgrade to a newer Mitmproxy because of some non-backwards compatible changes they made, see [https://bugzilla.mozilla.org/show_bug.cgi?id=1457274 Bug 1457274]).