You may have read our blog post about ARC here.
At the bottom of the post there are a number of resources listed:
For more information on ARC
ARC is not merely a protocol. There is a world of community support, and an ARC test suite (https://github.com/Valimail/arc_test_suite) that has proven useful in identifying specific issues and potential bugs to focus on at each interop. There are also numerous mature open source libraries that support ARC:
Since that article was posted, various mailing list software maintainers have updated their own documentation on supporting ARC and DMARC.
For Mailmain-specific information see this link: