Customizing licenses in metadata

Hello,

For context, I'm admin of a Moodle site which uses the H5P plugin (mod_hvp).

When we create new content, we would like to use the Metadata tab to ensure it's published under the right license.

There are a number of options there (copyright, various Creative Commons licenses, etc.) but none of them is applicable for us. Because we deal with endangered Indigenous knowledge, we use a more niche licenses called Tradition Knowledge Licenses (https://localcontexts.org/tk-licenses/).

Could anyone help me find where to add a custom license so that it shows up in the dropdown list?

Thanks for any pointers!