Publishing pEp in addons.thunderbird.net/ will bring more visibility to this great project. Currently searching for pgp there does not yield any result. This should be similar to looking for apps on play store or fdroid on android.
Again, another lack of collaboration between projects - all supposedly working towards giving freedom to users :( I think we can at least support GNU/Linux distros like Debian by providing native packages via official repos. I can help with creating debian package if someone at PEP is willing to collaborate with me if I need some help. I already maintain a lot of packages in Debian.