What is mean by application must run out of /opt?

Question

when I was going to rules of Ubuntu Apps Showdown, I found this rule:

• Application must run out of /opt.

What is means by this? Checkout Rules: http://developer.ubuntu.com/showdown/

Answer 1

In general, apps running from /opt are self-contained, i.e. they don't spread their footprint far and wide into /bin, /lib, /usr, etc. like normal APT-installed packages do. Basically, your app should stick to /opt except for any user data in /home/user as @konrad suggested.

Answer 2

If you run quickly submitubuntu, it'll create a package where everything runs from the /opt directory. Or at least, that's the answer I got when I asked this question.

Answer 3

All applications submitted through the Application Review Board (ARB) process (which I assume the app showdown is utilizing - although it does not say explicitly) must install and run from /opt/. The application can save data into a sane place in the home directory preferably following freedesktop.org suggestions.