Grey literature, in a nutshell, are all kinds of publications that - as far as I understand - are not properly published. This includes mainly reports of institutions or companies, or manuals, personal correspondance, ... The aspect I am focussing on is this:
Grey literature often has no proper license statement attached to it, making it unclear whether, and to what extent its contents may be cited, reproduced or shared.
When working with data from various sources, a similar problem can occur. I tentatively introduced the term grey data for that, but I would like to know: Are you aware of a more common term for this kind of data without clear publication status/usage rights?
Edit (trying to clarify): I am not looking for a in any sense legally "correct" term, but for a phrase that conveys the idea that between open data and confidential data there is a large spectrum of data that is available/released/.., but without an easily recognisable or ambiguous legal status (at least for a legal layperson). One example: the German Federal Network Agency (BNetzA) has been releasing a list of installed power plant capacity on their homepage. However, there is no statement attached for which purposes and under which conditions this dataset may or may not be used. Only through finding its additional release on govdata.de one can find a clear usage licence (here: DL-DE BY).