One of the key provisions of most open source licenses is the requirement to reinclude the license text in derived works. For example, the BSD licenses (all forms) say:



  1. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

In practice most software acknowledgements precede each license with the name of the library that it comes from, but note that there's no requirement for that in the license text: it requires the copyright holder to be named, but not the specific project. For example, the notice above might just say "Copyright 2021 Google" and leave you with no idea which of the many libraries from Google was used (and it might not be obvious if it's a proprietary program in binary form). I can imagine a program acknowledgements that says "includes software under the following licenses" and lists many licenses like this, but without a heading for each one saying where they came from.

Have I read this correctly? Obviously it's not very fair, either to the original authors or software users, to omit that information, but it seems like it would be legal to do so?

I'm also interested in other permissive licenses (e.g. Apache, MIT). The ones I've read all seem to have the same problem.

  • 1
    Is the work a source distribution or a binary one? For example, the zlib/libpng license gives an explicit requirement than an altered source version "must be plainly marked as such", but explicitly does not require a notice "if you use this software in a product."
    – Brandin
    Jul 22, 2021 at 14:58
  • @Brandin I'm thinking of binary distribution (statically linked). Partly because redistributions in source form are usually fairly easy to identify unless you very heavily modify. Jul 22, 2021 at 15:27
  • The "Copyright <year> <holder>" has nothing whatsoever to do with open source, it is a requirement (recommendation, really) in copyright law to mark your claim of right ownership.
    – vonbrand
    Jul 24, 2021 at 22:29
  • @vonbrand That doesn't have anything to do with my question. The other bit of the BSD license I quoted says why that copyright notice is relevant to open source: in order to obey the license terms, you "...must reproduce the above copyright notice". If you think that's unnecessary, you should complain to the authors of the BSD license, not people like me that are trying to follow it! Other common open source licenses have similar clauses, by the way. – Jul 25, 2021 at 23:16

1 Answer 1


Have I read this correctly? Obviously it's not very fair, either to the original authors or software users, to omit that information, but it seems like it would be legal to do so?

Yes, you have read it correctly and it is indeed legal to omit mentioning which third-party code a particular license statement refers to (assuming the project's is not referenced in a copyright line).

I am also not aware of any widely used licenses that have a requirement to mention the source project.

Mentioning where you got the code from or which library you are using is primarily a gesture of goodwill and not a legal requirement.

Some projects mention their copyright line as Copyright <year>, The <project> developers. Mostly this is done because they believe the list of names would be too long, but it can also be a way to ensure your project name gets acknowledged.

  • Thank you, I'm grateful you took the time to answer. But I can't mark it as accepted because you haven't cited any sources, so it gives the impression that you've just read the licence and told me your own interpretation. Your answer boils down to your first paragraph, "Yes, you have read it correctly ..." but you don't explain why you think that. Jul 30, 2021 at 11:18

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.