SubLib, the subtitle library used by Gnome Subtitles, has been merged into the Gnome Subtitles source code repository.
The original purpose of the SubLib subtitle library was to provide multimedia applications with a common and simple way to work with different file formats, performing file editing, searching, translation and synchronization. Since its creation, although some projects have used SubLib in order to take some concepts and ideas, as was the case with a couple of commercial applications, SubLib itself wasn't used by those projects. In fact, SubLib is currently only used by the Gnome Subtitles project.
That said, it was decided to merge its source code into Gnome Subtitles. This move not only eases the development of Gnome Subtitles, but also facilitates the tasks of packaging and releasing the application.