A TORRENT file is an information file for downloaders that support the TORRENT protocol. Torrent itself is a file-sharing protocol for the sharing of files. It's especially good for large files because it distributes the load over many users, while with http or ftp, the load has to be carried by a single server. However, TORRENT only works really well if there are enough distributors who also offer the appropriate file.
In addition to the illegal use of TORRENT files are now also offered by some download portals (for example for game patches) and many other websites. Games also use this technique (e.g., Company of Heroes, Blizzard Downloader)
A TORRENT file is usually very small, because in the TORRENT file are only information about the file, its size, checksum and information about so-called trackers. These files can be downloaded with any browser.
To download the actual file, you need a TORRENT download program (torrent client) or a browser that supports this protocol. If it is often loaded and offered files, the download rate is correspondingly high. If there are no distributors (seeder), you will not get the file. A TORRENT file is not a guarantee to get a specific file.