Vim License

With this license, you can use and distribute a software’s unmodified copy without any restrictions. With it, sections of the software can be distributed so long as the license text is included. Its main conditions include license and copyright notice, source disclosure, state changes, and same license.

Full License Text

VIM LICENSE

I)  There are no restrictions on distributing unmodified copies of [project]
    except that they must include this license text.  You can also distribute
    unmodified parts of [project], likewise unrestricted except that they must
    include this license text.  You are also allowed to include executables
    that you made from the unmodified [project] sources, plus your own usage
    examples and Vim scripts.

II) It is allowed to distribute a modified (or extended) version of [project],
    including executables and/or source code, when the following four
    conditions are met:
    1) This license text must be included unmodified.
    2) The modified [project] must be distributed in one of the following five
       ways:
       a) If you make changes to [project] yourself, you must clearly describe
          in the distribution how to contact you.  When the maintainer asks
          you (in any way) for a copy of the modified [project] you
          distributed, you must make your changes, including source code,
          available to the maintainer without fee.  The maintainer reserves
          the right to include your changes in the official version of
          [project].  What the maintainer will do with your changes and under
          what license they will be distributed is negotiable.  If there has
          been no negotiation then this license, or a later version, also
          applies to your changes. The current maintainer is Bram Moolenaar
          <Bram@vim.org>.  If this changes it will be announced in appropriate
          places (most likely vim.sf.net, www.vim.org and/or comp.editors).
          When it is completely impossible to contact the maintainer, the
          obligation to send him your changes ceases.  Once the maintainer has
          confirmed that he has received your changes they will not have to be
          sent again.
       b) If you have received a modified [project] that was distributed as
          mentioned under a) you are allowed to further distribute it
          unmodified, as mentioned at I).  If you make additional changes the
          text under a) applies to those changes.
       c) Provide all the changes, including source code, with every copy of
          the modified [project] you distribute.  This may be done in the form
          of a context diff.  You can choose what license to use for new code
          you add.  The changes and their license must not restrict others
          from making their own changes to the official version of [project].
       d) When you have a modified [project] which includes changes as
          mentioned under c), you can distribute it without the source code
          for the changes if the following three conditions are met:
          - The license that applies to the changes permits you to distribute
            the changes to the Vim maintainer without fee or restriction, and
            permits the Vim maintainer to include the changes in the official
            version of [project] without fee or restriction.
          - You keep the changes for at least three years after last
            distributing the corresponding modified [project].  When the
            maintainer or someone who you distributed the modified [project]
            to asks you (in any way) for the changes within this period, you
            must make them available to him.
          - You clearly describe in the distribution how to contact you.  This
            contact information must remain valid for at least three years
            after last distributing the corresponding modified [project], or
            as long as possible.
       e) When the GNU General Public License (GPL) applies to the changes,
          you can distribute the modified [project] under the GNU GPL version
          2 or any later version.
    3) A message must be added, at least in the output of the ":version"
       command and in the intro screen, such that the user of the modified
       [project] is able to see that it was modified.  When distributing as
       mentioned under 2)e) adding the message is only required for as far as
       this does not conflict with the license used for the changes.
    4) The contact information as required under 2)a) and 2)d) must not be
       removed or changed, except that the person himself can make
       corrections.

III) If you distribute a modified version of [project], you are encouraged to
     use the Vim license for your changes and make them available to the
     maintainer, including the source code.  The preferred way to do this is
     by e-mail or by uploading the files to a server and e-mailing the URL. If
     the number of changes is small (e.g., a modified Makefile) e-mailing a
     context diff will do.  The e-mail address to be used is
     <maintainer@vim.org>

IV)  It is not allowed to remove this license from the distribution of the
     [project] sources, parts of it or from a modified version.  You may use
     this license for previous [project] releases instead of the license that
     they came with, at your option.