To find the state of this project's repository at the time of any of these versions, check out the tags.
There were two purposes to this as a better alternative to XVideo: - video surfaces pass-through in GPU in case of hardware decoding, - scaled SPU blending in both software and hardware decoding cases. Both functions are now supported with higher priority by the OpenGL video output. Also the software case no longer works at all anyway.
VideoLAN code repository instance