Avogadro has a very open and active development community. Currently there are more than 10 active developers and other various contributers. If you are interested in working on or with Avogadro please look at the developer information that is available on the wiki and subscribe to the mailing list. You could also join the IRC channel (#avogadro on irc.freenode.net) and talk with other developers. For information on the internals of Avogadro and LibAvogadro, review the avogadro developer API.