It returns the app object.  
curl 127.0.0.1:8642/v1.0/515b65c12a26a0d9cf000003
{"_id":"515b65c12a26a0d9cf000003","api_token":"v9wpey3rqmnrokgu4hqia7zwehicb0vs","app_type":"ios","app_version_list":[["1.0","515b66582a26a0d9ed000002"],["total","51e99eb22a26a07445000001"],["0.4.2","525dd1b52a26a00263000002"],["1.0.0","53165f142a26a0a6a4000002"],["2.0.0","53165f142a26a0a6a4000003"],["1.0.2","537fd1702a26a07c9a000003"]],"developer_uid":"515b65b52a26a0d9cf000002","inactive":false,"is_huge_crapp":false,"itunes":"123456789","lib_versions":[["3.4.8","515b66eb2a26a0dab9000001"],["4.1.1","524cb6dc2a26a0c9d1000001"],["4.0.0","525dd1b52a26a00263000001"],["4.2.0","526023662a26a0427e000002"],["4.3.1","52e189fd2a26a08674000001"],["4.2.1","53165f142a26a0a6a4000001"],["4.3.4","537fd1702a26a07c9a000002"]],"name":"Sandbox","oauth":{"secret":"iov7sn9k6oyhzbenqvpwjdalsxbcr2my","key":"nlkmcgpnrhgruob7fbay6tqqyaio"},"pkg":"com.crittercismlibdemo","plan":"Premium","platform":"ios","settings":{"throttle_votes_earned":1,"moderate_feedback":0,"receive_daily_digest":0,"receive_first_error_email":1,"show_close_button":1,"timezone_offset":-7,"need_pkg":1,"feedback_autovote":0,"rate_after_load_num":5,"remind_after_load_num":5,"receive_forum_post_email":1,"alert_submitter_only":0,"default_votes":"3","daily_max_votes":"10","is_rate_after_load":0,"actions":{},"rate_message":"Would you mind taking a second to rate my app?  I would really appreciate it!","include_stacktrace_email":1,"rate_title":"Rate My App"}}