This week Firefox 21 was released and there are two features of it that have irritated me.

First off, nowhere did I see an obvious prompt or mention that there's now a feature (Firefox Health Report, FHR) that collects general browser, non-user data. It's not a big deal since this comprises anonymous browser statistics only. On the other hand, the fact that I didn't see any notification or an opt-in/opt-out prompt on upgrading irks me. (I only learned about it from The Register.)

From Mozilla's FHR FAQ:

"We believe in giving users power over data, even data like this that isn’t personally identifiable or linkable to our users. FHR gives Firefox users control over data submitted by their browser. Users can use FHR data to better understand their browser’s performance or stability by comparing it to that of aggregate data from other browser configurations. At any time users can disable the feature or delete data associated with their browser."

Fine. It would have been nice to, you know, actually make certain that users were aware of this feature though.

Secondly, and more directly annoying, left clicking on an MP3, which would show a save/open prompt, now starts playing the MP3 instead. (I'm assuming this feature is new in Firefox 21, since I can't remember it being present previously. I'm also aware that you can right-click, and then choose Save Link As..., but it's easier to just left-click.)

My initial thought was to check the list of MIME types (Options > Applications) to see if anything had changed. No, it still looked just as it did before:

Firefox MIME types

The about:config option to restore the original behaviour is to set media.windows-media-foundation.enabled to false, although this disable in-browser playback of some other media formats. Again, it's not a big problem, but it's counter-intuitive to let the user set an option that purportedly controls what happens when a link is clicked, and then ignore it for no discernable reason.