mit-license VS rootless-tweaks

IANAL, but common open source licenses is a Yes. Non-licensed works are legally murkier.

You have a derivative work based on the original. The author retains the copyright, but has granted some permissions within the license document. What you can and can't do will be spelled out there. For example, the MIT license expressly permits modification and sublicensing [0]. The GNU GPL3 is even more explicit, giving definitions to modify, distribute, their permissions, and the requirements for both [1]. Double-check what the terms of the license give you explicitly.

What if their is no license? I think that gets closer to the heart of the article. Imagine you come across a website design you like. What are the permissions for their HTML or CSS? By definition the distributor controls all aspects under copyright. But if you only use a small part, you can defend yourself under Fair Use. But this is murky legal territory, as Entertainment companies and individuals have sued each other over Music Samples and their relevant copyright and licensing.

[0]: https://mit-license.org/

[1]: https://www.gnu.org/licenses/gpl-3.0.en.html

An MIT License (“Permission is hereby granted, free of charge . . . to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software…”)

The 2003 source release of Duke3D under GPL includes a ZIP file with Ken Silverman's Build engine and the same weird license. I don't know if the Duke code can be compiled without Ken's code. Ken writes on http://www.advsys.net/ken/buildsrc/default.htm that the custom license is to stroke his own ego. Why he didn't at one point switch to one of the many short GPL-compatible licenses such as MIT's is something only he and his ego can answer.

For example, the MIT license. https://mit-license.org/

The app is licensed under the MIT License

The Laravel framework is an open-sourced PHP web framework that allows developers to create dynamic and scalable web applications. The source code of Laravel is hosted on GitHub and released under the MIT license.

No because the MIT license requires that it be included in any copies and/or derivatives:

MIT projects only need to include the MIT license with the build. A copy of the source code is not required, only a copy of the MIT license. I believe re-licensing is also allowed, MIT is about as permissive as you can get.