https://creativecommons.org/weblog/entry/44030
Detailed analysis: https://wiki.creativecommons.org/ShareAlike_compatibility:_FAL
Comparison: https://wiki.creativecommons.org/ShareAlike_compatibility_analysis:_FAL
In summary: The latest version of the Free Art License (version 1.3) has become the first third-party license compatible with the Creative Commons Attribution-Sharealike 4.0 License, meaning that people like us can use the two licenses interchangeably, or mix works using the two licenses together. We also can dual-license new works under both licenses so that people can have a choice as to what license they want to use.