and released with a note that the format is subject to change without notice, and that the file should only be read or written with libraries provided by the developer. In other cases, the specification of the data encoding format may not be publicly documented at all; in some cases, the format may only be released to those who have signed non-disclosure agreements. A proprietary format can also be a file format whose encoding is in fact published but is restricted through licenses such that only the company itself or licensees may use it.

Proprietary