Open-ended way to install software from local mediums

Synaptic's "Add CD-ROM" option is not nearly as flexible as it could be. The feature makes too many expectations, such as what medium is being used to store a repository. What if someone wants to update from a DVD, a flash drive, a disk image or a directory already on their computer? This specification aims to address that by creating a more fluid and easy way to install software from any storage medium.