Z:gnu-www-ja-free-sw--b363d8-In the GNU project, we use cop/en

In the GNU project, we use copyleft to protect the four freedoms legally for everyone. We believe there are important reasons why it is better to use copyleft. However,  noncopylefted free software is ethical too. See Categories of Free Software for a description of how &ldquo;free software,&rdquo; &ldquo;copylefted software&rdquo; and other categories of software relate to each other.