Which kind of software is released into the public without retaining copyright?

Public Domain software is a type of software that has been released into the public without retaining copyright protection. This means that the creator has relinquished all rights to the software, allowing it to be freely used, modified, and distributed by anyone without permission or payment. This is a significant aspect of Public Domain, as users have the freedom to adopt it for various purposes without legal constraints.

The concept of Public Domain is particularly important in fostering an open-source environment where innovation can thrive, as developers and users can build upon existing works. In contrast, the other options pertain to different contexts: "Publisher" refers to entities that release software but typically retain copyright, "Piracy" involves the illegal copying and distribution of software, and "Procedure" does not relate to software distribution. By understanding Public Domain, one recognizes the role of copyright and intellectual property in software development and the implications of their absence.