upstream no longer maintained

https://github.com/twanvl/MagicSetEditor2 has not been updated in 4 years, since then the community around custom cards has moved on to creating a new fork (and then again)

this repo still provides mse 2.1.2, the forked version is currently 2.5.8, the older version will continue working as is while unmaintained but it's worth knowing that a newer version that is compatible with newer card designs etc exists