Most applications involved are SIP servlet applications.
Messaging is supported by the Proxy Registrar application (proxyregistrarear-188.8.131.52.0.ear), presence is supported by the Presence application (presenceapplicationear-184.108.40.206.0.ear). Other applications are involved for buddy list and presence rules related operations, including aggregation proxy (aggregationproxyear-220.127.116.11.0.ear) and auth proxy (authproxyear-18.104.22.168.0.ear). Other applications in there include Subscriber Data Services (subscriberdataservices-22.214.171.124.0.ear) for user/security services, and STUN (stunprimear-126.96.36.199.0.ear) for providing support for traversal through NATs, etc.
What exactly are you looking for?
Each application is exploded to the following dir:
The above location is for all-in-one-managed server installation. For all-in-one-admin server, you will find the exploded apps at:
In that dir, you will find a list of all apps deployed. You can navigate to the required app directory and look at the exploded files.