Hey Grant,
(I’m not a license attorney…..certainly the first word of advice in any situation like this is that you should consult one, for an official answer to your questions regarding the licenses and terms of use laws in your country, state, region, etc….)
However, speaking from personal experience and as a developer myself as well as content creator and user of others content in my own work, I am a supporter of many different types of licensed and also free use rights projects.
Not sure your specific situation, but at least with what I do, when it comes to digital media and content creation or use of content in my own derived works in general, there are certain licenses that have “use rights” or “terms of use” rights which should be provided to you at the time of purchase, or at the time you’ve obtained something from someone else. Perhaps even the “terms and conditions” or “license” link off the website of your source will be able to guide you.
You should always consult the source from which you are concerned. AT MINIMUM if there is one included, make sure you read any license agreements provided to you, don’t assume you have the right to do something, even if you didn’t get one……ask for it if all else fails.
You don’t want to run the risk of being rejected by your clients legal dept, or being sued by your source, because you didn’t take the time to do your due diligence and investigate to get proper documentation.
There are many many many types of licenses as there are developers, companies, and programs.
For example, Creative Commons, GPL, Public Domain, BSD License, MIT License, etc, are all different licenses that may be included with something you have now, use, or utilize in some way today.
Just remember, sometimes licenses will be specific, and sometime they will not….don’t assume. Make sure you research information, such as what you are doing now to get definitive answers specific to what you are giving or selling to someone else, either commercially, or as a person / friend, etc….
Also remember to provide your own license, either in addition to, or in a license for which you have the proper rights of your original license, and your own rights accounted for.
Here is a good example and good resource in general to get you started on understanding more about licensing that you may have available to yourself to utilize…but again, at any rate, the best consultation is with an attorney specializing in Copywriting, Licensing etc…
Just make sure you know and understand what you are able to do with the stuff you already do now. As long as you’re inside the law of the license, and the law of the “terms”, it would be my opinion you could provide such documentation along with your distributed version that would include license information to suffice for your clients legal team.
https://en.wikipedia.org/wiki/Licenses
(Wikipedia is licensed under a Creative Commons license)
Link to license – https://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License
Link to Wikipedia Foundations Terms of Use Page:
https://wikimediafoundation.org/wiki/Terms_of_use