I put together a little jetpack that tells you if Firefox's accessibility service is actually running in your browser. It is basically David Baron's "about:accessibilityenabled" extension but as a jetpack. If you want to give it a whirl, strap it on.
You'll need to grab Jetpack if you don't have it already. Alternatively you can just use David Baron's handy about:accessibilityenabled extension.
Aside: we've noticed the gecko accessibility service is being used in some unusual places, for example, by some desktop anti-spyware; leading to unnecessary performance degradation. If you discover that our accessibility service is unexpectedly running in your Firefox session, please consider contacting me so we can figure out why...
Thanks for reading.