Hi,
The link below includes documentation about a proposed CSV-based file format for fork deployment data (tentative config filename: forks.csv). This is planned to be used by my reference implementation of bip-genvbvoting (which is still in development - TBA later).
Other BIP9 improvement proposals are of course encouraged to use this format, and I'm happy to discuss extensions of it for things like supporting flag days or direct-to-activation transitions.
Regards,
Sancho