Open source? yes
Source code: https://github.com/magarena/magarena/releases/download/1.81/Magarena-1.81.zip
Description: it's a single-player fantasy card game played against a computer opponent with the rules based on Magic: The Gathering.
I had a look at this today.
To build this package, you need apache groovy which is not in the repository.
But to build groovy, you need asciidoctor which is also not in the repository.
I didn't go further.
This has sat in accepted for inclusion for over a year. Clearly, there is a lack of demand for the inclusion of this software, nobody has stepped up to provide a completed patch, maintain it, and properly integrate it. Closing as a result. Feel free to reopen but only when someone offers a patch via our proper patch submission methods and volunteers to be maintainer.