who do i talk to in order to propose an extension to #vcard? do they have a mailing list or something?

the extension in question: new parameters X-START-DATE and X-END-DATE (?) that can be used to denote a date range during which a given contact had specified records.

example use case: someone has a phone number from 2011 to 2014. i want my old SMS convos to show their contact info *only* for messages within that date range. new SMS should NOT be linked to the same contact.

i've been thinking about this on and off for a long time https://wiki.trwnh.com/wrong/address-books/ (that page is dated 2019)

i think in vcard-rdf you have some level of extensibility because you can just make your hasAddress or hasTelephone point to a node that has properties from some other vocab, like as:startTime and as:endTime for example. but this isn't directly translateable back to an actual #vcard file afaik