IIRC, the package description said something similar to "this is the iNotify version of the syncthing binary", or I may be completely wrong. I need to get previous versions and look to the descriptions of each :)
You might mix that up with syncthing-inotify, which was an external small inotify watcher that then pinged syncthing via its API. It was the recommended way to get inotify support till the functionality got merged.
Maybe, however all my Debian installations are very strict in their repository configuration, and I'm failing to see syncthing-inotify package in Debian snapshots server [0].
...or maybe I'm making all these up from all the things I read while researching syncthing, who knows :)
Regardless of all, it's working very well and it's dependable now, and it's the point I think :D
Addenda: Actually, forgetting all little details about it is a reliable sign of an application working well and just disappears to the background IMHO.