Plan S is an initiative for open-access science publishing launched in 2018[1][2] by "cOAlition S",[3] a consortium of national research agencies and funders from twelve European countries. The plan requires scientists and researchers who benefit from state-funded research organisations and institutions to publish their work in open repositories or in journals that are available to all by 2021.[4] The "S" stands for "shock".[5]
Per 2017 figures, the mandate of Plan S will cover about 6% of worldwide research articles, including about one third of articles in Nature and Science. Major publishers have been planning to accommodate this mandate by offering (or allowing) open access options to authors.[6]
De S staat voor shock. (Robbert-Jan Smits, presentation at the Physics@Veldhoven conference, 22 January 2019).
bra21
was invoked but never defined (see the help page).