Digital resources and their metadata must always, without exception, include a license that describes under which conditions the resource can be used, even if that is “unconditional”. By default, resources cannot be legally used without this clarity. Note also that a license that cannot be found by an agent, is effectively the same as no license at all. Furthermore, the license may be different for a data resource and the metadata that describes it, which has implications for the indexing of metadata v.v. findability. It also reiterates the need to separate and permalink data and metadata. This is a clear public domain statement, an equivalent such as terms of use or computer protocol to digitally facilitate an operation (for instance a smart contract). Thus, the absence of a license does not indicate “open”, but rather creates legal uncertainty that will deter (in fact, in many cases legally prevent) reuse. Note also that the combination of resources with permissive as well as more restrictive license conditions may lead to adverse effects, and ultimately preclude the use of the combined resources for particular purposes. In order to facilitate reuse, the license chosen should be as open as possible.(see additional criteria GFF)