I think that we are all testers to a certain extent.

I remember trying to install something from Extras and receiving a message saying it was missing Siimplejson. (In fact, I remember coming across this issue many months ago, perhaps more than a year. Did you SEARCH before answering this question?)

I can't remember what it was that I was trying to install. I'll try to find out.
Edit: Oops,I just remembered that I have mostly switched to Mer and can't test on my N810. My N800 is at home and I won't be there for a few weeks.

But I still remember trying to install some app recently and running into a message saying it was missing simplejson, and I still remember this coming up in the past as well.