The possibility of editing metadata of PDFs is an excellent tool.
Under "Additional metadata" there is a "Copyright status" drop-down that only has "Unknown", "Copyrighted" and "Public Domain".
I'd like to suggest addition of Creative Commons licenses in that drop-down list, since CC-licensed works cannot really fit in any of the 3 available categories.
Also, if possible, when they are chosen the next fields, "Copyright notice" and "Copyright Info URL" could be automatically filled with the matching text and url.
That would be a wonderful functionality.
I see there are some standard fields for storing that like http://purl.org/dc/terms/licensehttp://purl.org/dc/terms/LicenseDocument
defined inhttp://dublincore.org/documents/2012/06 ... lements#H3