Full article about it all is here: http://techdows.com/2015/08/shocking-firefox-silently-installs-adb-helper-and-valence-add-ons.html
Other than that, webide can have access as well, will be better to shutdown it in about:config
few usefull for it all commands:
devtools.webide.enabled - false;
devtools.webide.autoinstallADBHelper -false;
devtools.webide.autoinstallFxdtAdapters -false;
devtools.webide.autoConnectRuntime -false;