Lisencing a package that includes data from many packages

I'm currently trying to make my new package paletteer CRAN ready and I'm a little puzzled with how to get the licensing and copyright done right.

The package includes data from 24 different package, which is combined in the data-raw (here) to create a list used in the package itself. Since the extract of data have been done beforehand I don't need to depend on the packages directly but I still need to properly attribute their work.

As I understand it, it is normally done by added the people in the Authors@R field in the DESCRIPTION file as contributors. However due to the number of people involved it is normally requested that a COPYRIGHTS or AUTHORS file is added in the inst/ folder. But I haven't been able to find any examples or guidelines about how these files should be structured.

Can it be done by filling the AUTHORS file with what would have been set as the Authors@R field?

Some examples from packages on CRAN:

It looks like they follow the debain copyright file format.

In case you're interested, here's the code I used to the Copyrights field of package descriptions:

ip <- installed.packages()
copyrights <- lapply(ip[, "Package"], packageDescription, fields = "Copyright")
Filter(Negate(, copyrights)