: This is a technical term for the folder level above the current one in a file system. In web searches, it is often associated with finding open directories of files (like movies or music). In the NFT space, it might be used as a stylistic naming convention or to imply a "root" collection.
: MP4 files are linked via the animation_url in the NFT's JSON metadata, allowing the video to play directly on the OpenSea item page.