I read this article on the basics of pinning. I have a question, I installed debian 8 jessie. There are a few things that I am having trouble with.I would like to install a few packages, like firefox. When I run apt-get install firefox I get this error:  apt-get install firefoxReading package lists... DoneBuilding dependency tree       Reading state information... DonePackage firefox is not available, but is referred to by another package.This may mean that the package is missing, has been obsoleted, oris only available from another sourceE: Package 'firefox' has no installation candidateHow can I find out which repositories to add to get the packages that I want?I would like to keep the core stable repo but things like firefox and other apps I can pull from more bleeding edge repos.How can I do this?
Package firefox is not available
debian;firefox
In Debian, firefox is called iceweasel and has a different icon.  I believe that they are functionally equivalent except for the icon.  Similarly Thunderbird is called icedove in Debian.Debian has most packages.  If you want to have access to all Debian repos, you should check your /etc/apt/sources.list{,.d/*} and make sure the lines that start with deb end with main contrib non-free.There's also official Debian backports (or have been in the past) where later package versions are backported and build for older Debian releases.Beyond that, there's web searching!