Creative Commons Rights Expression Language

Creative Commons Rights Expression Language (ccREL) is a proposed Rights Expression Language (REL) for descriptive metadata to be appended to media that is licensed under any of the Creative Commons licenses. According to the draft submitted to the W3C, it is to come in the forms of RDFa for (x)HTML pages and XMP for standalone media.

Source: Wikipedia — Creative Commons Rights Expression Language (CC BY-SA 4.0)