Thanks! Wrt "There are several DOI issuers who act a bit like letsencrypt" -- I haven't seen any that are free like letsencrypt, did you have in mind any concrete issuer?
Since we're on this topic, anybody knows a way to get (very) cheap DOIs? I know people who try to maintain independent repositories of academic papers, and are successful at it, but don't have the budget to get standardly-priced DOIs for all those articles - one of the few complaints their users have.
$ khal new tomorrow 11:00 help Bob catchup python