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For the developers' and authors' protection, the GPL clearly explains that there is no
warranty for this free software. For both users' and authors' sake, the GPL requires that
modified versions be marked as changed, so that their problems will not be attributed
erroneously to authors of previous versions.
Some devices are designed to deny users access to install or run modified versions of the
software inside them, although the manufacturer can do so. This is fundamentally
incompatible with the aim of protecting users' freedom to change the software. The
systematic pattern of such abuse occurs in the area of products for individuals to use, which
is precisely where it is most unacceptable. Therefore, we have designed this version of the
GPL to prohibit the practice for those products. If such problems arise substantially in other
domains, we stand ready to extend this provision to those domains in future versions of the
GPL, as needed to protect the freedom of users.
Finally, every program is threatened constantly by software patents. States should not
allow patents to restrict development and use of software on general-purpose computers,
but in those that do, we wish to avoid the special danger that patents applied to a free
program could make it effectively proprietary. To prevent this, the GPL assures that patents
cannot be used to render the program non-free.
The precise terms and conditions for copying, distribution and modification follow.
TERMS AND CONDITIONS
0. Definitions.
“This License” refers to version 3 of the GNU General Public License.
“Copyright” also means copyright-like laws that apply to other kinds of works, such as
semiconductor masks.
“The Program” refers to any copyrightable work licensed under this License. Each licensee
is addressed as “you”. “Licensees” and “recipients” may be individuals or organizations.
To “modify” a work means to copy from or adapt all or part of the work in a fashion requiring
copyright permission, other than the making of an exact copy. The resulting work is called
a “modified version” of the earlier work or a work “based on” the earlier work.
A “covered work” means either the unmodified Program or a work based on the Program.