I'm reasonably sure there is no authorative source for anything like this in this generality. Only in recent years a move is made to require researchers and contractors of grants to follow more open standards so that research results and code produced is made available to the public in an open manner. This is still not the norm (everywhere). And there is no central registry.
Thus: the copyright will need to be indicated within the repositories, on the pages, in the documents or the sources you want to use, thus in the usual places. If you find no information, the general rule applies: "all rights reserved". It's tedious, but it never hurts to ask the authors / copyright owners if the information is unclear or missing. It definitely is worth continuing to lobby for public availability and access to results and works funded by public money.