License information for figures in Org mode?

[Jens Lechtenboerger <lechten@wi.uni-muenster.de>]

Hi there,

I’ve written code based on Org mode to generate Open Educational
Resources (OER, learning material under free licenses, typically
variants of Creative Commons), which include figures with proper
license attribution (source, author, license) [1].  If you ever wanted
to publish OER yourself, you are probably aware of the hassle of doing
that properly as figures usually do not embed license information,
which needs to be obtained and annotated separately.

Currently, I use Org macros to embed figures, e.g.:
#+BEGIN_SRC org
{{{reveallicense("./figures/org/jitt/JiTT-Java-MX.meta","33vh","figure fragment appear")}}}
#+END_SRC

The meta file in the first argument uses an ad-hoc text format,
embedding a path for the figure along with licensing information
inspired by standard metadata vocabularies, e.g.:
#+BEGIN_SRC emacs-lisp
((filename . "./figures/org/jitt/JiTT-Java-MX.png")
 (licenseurl . "https://creativecommons.org/licenses/by-sa/4.0/")
 (licensetext . "CC BY-SA 4.0")
 (cc:attributionName . "Jens Lechtenbörger")
 (cc:attributionURL . "https://gitlab.com/lechten")
 (dc:source . "https://gitlab.com/oer/figures/blob/master/org/jitt/JiTT-Java-MX.org")
 (sourcetext . "GitLab")
 (dc:title . "Improved Java MX understanding")
 (texwidth . 0.9)
)
#+END_SRC

Currently, export to LaTeX (and, thus, PDF) and reveal.js (HTML with
RDFa) are supported (templates and the essential function
reveal-export-attribution are in [2]).

The above macro uses eval, whose syntax differs between released Org
mode versions and the master branch, which implies that I need to
reconsider my approach.  Any ideas or interest how such functionality
could be integrated into Org mode in general?

Best wishes
Jens

[1] https://gitlab.com/oer/emacs-reveal
[2] https://gitlab.com/oer/emacs-reveal/blob/master/reveal-config.el