These aren't "proper" debs though -- they're not provided by the distribution, don't use the standard build tools, and so on. The closest analogy I can think o

These aren't "proper" debs though -- they're not provided by the distribution, don't use the standard build tools, and so on. The closest analogy I can think of is the new packages you get from the paid portion of the Ubuntu App Store (ie, not universe), and those indeed conform to the /opt/vendor standard (with a few exceptions for things like a .desktop file).