Fantastical can be linked via UI scripting using Hook’s scripts. if you want to link Fantastical data programmatically, then this Twitter thread is relevant to you… You might want to simply “like” the relevant tweet.
FYI There’s a signup email address for the upcoming manifesto on linking on https://hookproductivity.com/help/integration/data-linkability-and-why-it-matters/ . Several prominent devs of linkable apps that users on this forum love have signed up . You’ll see their names on the manifesto when it is published.
A preamble to the manifesto will be published in The Future of Text book which will be launched later this month.