We ran with this, and implemented a new taxonomy called “Licence”. This is now available when adding or editing a product as an optional field. You can select the licence by its short name, and the taxonomy term descriptions page has more details about what it is.
Licences from the taxonomy are displayed under the product image on the product pages, just like other taxonomies. In the Details tab of your products, it displays the full licence name with a link to the official licence text where applicable.
Products can now be filtered by licence when searching, and we migrated products that use the short licence names as custom tags to use the new taxonomy terms instead.
This should go a long way to standardising how licences are used and displayed 