Merge pull request #1889 from raybellwaves/patch-1

Author: beckermr

src/maintainer/adding_pkgs.rst

@@ -761,7 +761,7 @@ For the ``about: license`` entry in the recipe ``meta.yaml``, using a SPDX ident
 See `SPDX license identifiers <https://spdx.org/licenses/>`__ for the licenses.
 See `SPDX license exceptions <https://spdx.org/licenses/exceptions-index.html>`__ for license exceptions.
 See `SPDX specification <https://spdx.org/spdx-specification-21-web-version>`__ Appendix IV
-for the specification on expressions.
+for the specification on expressions. Some examples of these are:
 
 .. code-block:: none
 
@@ -775,6 +775,7 @@ for the specification on expressions.
    MIT
    MIT AND BSD-2-Clause
    PSF-2.0
+   Unlicense
 
 .. _third_party_package_licenses: