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2026

Archived version 1 of 2. This is how the model read before it was corrected. It is shown read only. The current version is here.

Nethack General Public License

Also known as NGPL, Nethack General Public License.

Commercial use
allowed
Share alike
required
Attribution
required (keep the copyright and license notices)
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Canonical URI https://dalicc.net/licenselibrary/NGPL

Permissions

  • Charge distribution fee from the text Charging a fee for the act of providing a copy of the work to someone else.
  • Commercial use from the text Using the work to generate income, directly or indirectly, for example by selling it or by using it in advertising.
  • Derivative works from the text Distributing an adaptation of the work and making it available to the public.
  • Derive from the text Creating a new work from the work, such as a translation, adaptation or arrangement of it or of a part of it.

    Duties

    • Attribution from the text Giving credit to the copyright holders or authors of the work, in the form the licensor asks for.
    • Modification notice from the text Marking a changed work as changed, saying how it differs from the original and keeping earlier notices of change.
    • No-warranty notice from the text Attaching a notice that the work is provided without any warranty.
    • Notice from the text Notice: keeping the license and copyright notices with every copy.
    • Source code from the text Providing access to the source code of the work with every copy distributed.
  • Display from the text Showing the work to the public without making a copy the viewer keeps.
  • Distribute from the text Providing copies of the work to the public or to anyone else.

    Duties

    • Attribution from the text Giving credit to the copyright holders or authors of the work, in the form the licensor asks for.
    • No-warranty notice from the text Attaching a notice that the work is provided without any warranty.
    • Notice from the text Notice: keeping the license and copyright notices with every copy.
    • Source code from the text Providing access to the source code of the work with every copy distributed.
  • Modified works from the text Distributing a modified version of the work that does not amount to a new, derivative work.
  • Modify from the text Altering the work, for example by updating it, without creating a new work; an alteration that creates a new work is Derive.

    Duties

    • Attribution from the text Giving credit to the copyright holders or authors of the work, in the form the licensor asks for.
    • Modification notice from the text Marking a changed work as changed, saying how it differs from the original and keeping earlier notices of change.
    • No-warranty notice from the text Attaching a notice that the work is provided without any warranty.
    • Notice from the text Notice: keeping the license and copyright notices with every copy.
    • Source code from the text Providing access to the source code of the work with every copy distributed.
  • Present from the text Performing the work in public, including by broadcast or other communication to the public.
  • Reproduce from the text Making copies of the work in any form.

Prohibitions

  • Change license from the text Not permitted: Change license. Replacing the license of the work, or of an adaptation, with another license, or changing its terms.
  • Sublicense from the text Not permitted: Sublicense. Granting a third party rights in the work under a license of the licensee's own, rather than passing on the original license.

License-wide duties

  • Share alike from the text Adaptations have to be licensed under the same license or one the license names as compatible.

Further terms

These are the things the license says about itself beyond the acts it permits, forbids and requires: when it ends, how long there is to put a breach right, which law governs it, and so on. A term that comes from the DALICC vocabulary links to its definition.

Terminates on breach
Yes

Clauses

Additional clauses

b) cause the whole of any work that you distribute or publish, that in whole or in part contains or is a derivative of NetHack or any part thereof, to be licensed at no charge to all third parties on terms identical to those contained in this License Agreement (except that you may choose to grant more extensive warranty protection to some or all third parties, at your option)

Info

Target asset types
Software
Region / jurisdiction
Worldwide
Validity
Perpetual
Source
https://opensource.org/license/NGPL
Legal code
https://opensource.org/license/NGPL
This description is published under
https://dalicc.net/licenselibrary/CC-BY-4.0
SPDX identifier
NGPL on the SPDX license list
DALICC identifier
NGPL

This record is published under CC BY 4.0. Credit it as: DALICC License Library, DALICC - Verein zur Förderung der Rechtssicherheit in der Datenbewirtschaftung, https://dalicc.net, CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). The license it describes belongs to its publisher.

History

This license model has 2 versions. Version 2 is the one served today; every earlier version keeps its own address, so a conclusion drawn from one of them can still be checked against it.

  1. Version 2 current2026-09-24 Giray Havur

    The changes since version 1 recorded which sentence of the text each statement rests on and named the license the record itself is published under.

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    7 changes

    • changed duty cc:ShareAlike

      was duty cc:ShareAlike

      Manual edit The statement now quotes the sentence of the licence text it rests on: "cause the whole of any work that you distribute or publish, that in whole or in part contains or is a derivative of NetHack or any part thereof, to be licensed at no charge to all third parties on terms identical to those contained in this License Agreement (except that you may choose to grant more extensive warranty protection to some or all third parties, at your option)"

    • changed permission dalicc:chargeDistributionFee

      was permission dalicc:chargeDistributionFee

      Manual edit The statement now quotes the sentence of the licence text it rests on: "You may charge a distribution fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee."

    • changed permission odrl:derive with duties [cc:Attribution, cc:Notice, cc:SourceCode, dalicc:modificationNotice, dalicc:noWarrantyNotice]

      was permission odrl:derive with duties [cc:Attribution, cc:Notice, cc:SourceCode, dalicc:modificationNotice, dalicc:noWarrantyNotice]

      Manual edit Its duty dalicc:noWarrantyNotice quotes "You may copy and distribute verbatim copies of NetHack source code as you receive it, in any medium, provided that you keep intact the notices on all files that refer to copyrights, to this License Agreement, and to the absence of any warranty; and give any other recipients of the NetHack program a copy of this License Agreement along with the program."

    • changed permission odrl:distribute with duties [cc:Attribution, cc:Notice, cc:SourceCode, dalicc:noWarrantyNotice]

      was permission odrl:distribute with duties [cc:Attribution, cc:Notice, cc:SourceCode, dalicc:noWarrantyNotice]

      Manual edit Its duty dalicc:noWarrantyNotice quotes "You may copy and distribute verbatim copies of NetHack source code as you receive it, in any medium, provided that you keep intact the notices on all files that refer to copyrights, to this License Agreement, and to the absence of any warranty; and give any other recipients of the NetHack program a copy of this License Agreement along with the program."

    • changed permission odrl:modify with duties [cc:Attribution, cc:Notice, cc:SourceCode, dalicc:modificationNotice, dalicc:noWarrantyNotice]

      was permission odrl:modify with duties [cc:Attribution, cc:Notice, cc:SourceCode, dalicc:modificationNotice, dalicc:noWarrantyNotice]

      Manual edit Its duty dalicc:noWarrantyNotice quotes "You may copy and distribute verbatim copies of NetHack source code as you receive it, in any medium, provided that you keep intact the notices on all files that refer to copyrights, to this License Agreement, and to the absence of any warranty; and give any other recipients of the NetHack program a copy of this License Agreement along with the program."

    • changed prohibition dalicc:sublicense

      was prohibition dalicc:sublicense

      Manual edit The statement now quotes the sentence of the licence text it rests on: "You may not copy, sublicense, distribute or transfer NetHack except as expressly provided under this License Agreement."

    • added dct:license <https://creativecommons.org/licenses/by/4.0/>

      Manual edit Every record is published under CC BY 4.0. cc:license names the record DALICC keeps of that licence; dct:license now names it by the address Creative Commons publishes it at, so that a consumer matching the canonical IRI finds it.

  2. Version 1

    Created from the license text on 2026-09-15 (Reciprocal and source-available).

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Every change names the reason behind it: a finding of the content review, one of its library-wide decisions, the metadata that review wrote onto every record, or a hand edit. None of it is legal advice.

Nothing on this page is legal advice. What a license means is decided by its text; ask a legal advisor before you rely on it.