Libpurple is the library which provides network-level connectivity for most services in Adium. Like Adium itself, it is licensed under the GPL. In addition to Adium, libpurple is the core of the Linux and Windows IM clients Pidgin and Finch. It is described further by a page in the Pidgin wiki.
Libpurple was previously named Libgaim.
The following notes are for use by the Adium team.
Propagating a tagged release to a specific branch (e.g. 2.7.4):
mtn explicit_merge t:v2.7.4 h:im.pidgin.adium im.pidgin.adium
This merges the tagged revision v2.7.4 with the head of the branch (im.pidgin.adium) and puts the result on im.pidgin.adium. This is the alternative to a simple
mtn propagate im.pidgin.pidgin im.pidgin.adium
which is equivalent to
mtn explicit_merge h:im.pidgin.pidgin h:im.pidgin.adium im.pidgin.adium
and would therefore merge up to the HEAD of im.pidgin.pidgin.