A launchd job without plist file, how does that work and how to find what job triggers it?
launchd jobs can be submitted directly (through launchctl, and likely through cocoa code) without using a plist file. Since I see this line:
parent bundle identifier = com.xunlei.Thunder
that suggests the application with that bundle identifier (probably 'Xunlei Thunder', a peer-to-peer networking thing) is setting up a helper app (ThunderHelper) to run independently in the background.