OptionalactionsOptionalclassOptionaldescriptionSentence introducing the card, shown between the heading and the first section.
OptionalfilterWords the card is found by that are not written on it, for a card with no name of its own or one whose name says less than what it holds. Reuse a sentence the page already has rather than inventing words for it: every word in it becomes one the card can be found by.
OptionalfilterShows the card only while a filter is running, for content that is there to be found rather than read: a page's own actions, which a search cannot otherwise reach, named and pointing at the page they are carried out on.
Optionalheading
Controls for the card as a whole, kept at the far end of its heading — a help mark, or a button that adds to what the card holds.
Taken as children rather than named one by one, so that the card needs no import of its own for them:
Cardis in the login and setup bundles, which have no business pulling in the app a help mark would reach for.