LICENSE.d is a collection of "add-ons" to common Open Source software licenses, to be included as named files in a LICENSE.d directory, along with the original, unmolested LICENSE text.
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NONO allows distributing copies without preserving copyright and other notices, turning MIT, BSD-2-Clause, or similar into something close to FPL-1.0 / 0BSD.
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IO declares maintainers' expectation that contributors will license their work on the same public license terms, a bit like section 5 of Apache-2.0.
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NOSRV makes double-extra-clear that the Open Source software license doesn't obligate contributors to provide ongoing services to anyone.
Licenses are prescription-strength legal devices, and messing with them is risky business. If you have serious questions about how you should license your software, consult a lawyer.
Do not put confidential information about you, your work, or your clients in issues or pull requests. Do not ask for legal advice on GitHub, or try to disguise requests for legal advice as general questions or hypotheticals. You don't want legal advice from anybody dumb enough to fall for that.