--- a/testing/taskcluster/scripts/tester/test-linux.sh
+++ b/testing/taskcluster/scripts/tester/test-linux.sh
@@ -106,16 +106,22 @@ if $NEED_WINDOW_MANAGER; then
     # Turn off the screen saver and screen locking
     gsettings set org.gnome.desktop.screensaver idle-activation-enabled false
     gsettings set org.gnome.desktop.screensaver lock-enabled false
     gsettings set org.gnome.desktop.screensaver lock-delay 3600
     # Disable the screen saver
     xset s off s reset
 fi
 
+# For telemetry purposes, the build process wants information about the
+# source it is running; tc-vcs obscures this a little, but we can provide
+# it directly.
+export MOZ_SOURCE_REPO="${GECKO_HEAD_REPOSITORY}"
+export MOZ_SOURCE_CHANGESET="${GECKO_HEAD_REV}"
+
 # support multiple, space delimited, config files
 config_cmds=""
 for cfg in $MOZHARNESS_CONFIG; do
   config_cmds="${config_cmds} --config-file ${cfg}"
 done
 
 if [ ${SKIP_MOZHARNESS_RUN} == true ]; then
   # Skipping Mozharness is to allow the developer start the window manager