purl for PPAs?

[dodys]

In Ubuntu ecosystem, it is possible to provide .deb files through a PPA. PPAs are both used for building and distributing packages. For more information:
https://launchpad.net/ubuntu/+ppas

For example, you can install firefox .deb from a PPA:
https://launchpad.net/~mozillateam/+archive/ubuntu/ppa

Do we need a new type for it or should we add a ppa namespace?

[pombredanne]

That's a good question... @dodys do you mind to ask around for folks to chime in? ideally from launchpad? and a question is whether the type is ppa or launchpad?
I am making this a discussion until we get some feedback?