It's proprietary software. They release the source for any of the licensed components that they use that require source to be made available. Just like Apple

It's proprietary software. They release the source for any of the licensed components that they use that require source to be made available. Just like Apple does for OS X at https://opensource.apple.com/releases/ https://opensource.apple.com/releases/ The fact that such downloads exist does not mean that the synology software is open source. Anyone who says otherwise is lying or misinformed.