/usr/share/upstart/sessions/bluez-mpris-proxy.conf is in ubuntu-touch-session 0.108+16.04.20160407-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 | description "BlueZ MPRIS proxy"
author "Simon Fels <simon.fels@canonical.com>"
start on started dbus
stop on session-end
respawn
exec /usr/lib/bluetooth/mpris-proxy -s core.ubuntu.media.Service
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