+\ExplSyntaxOn
+\newif\if@kivi@infobox
+\newif\if@kivi@footer
+\keys_define:nn {kiviletter} {
+ infobox .choices:nn = {true,false} {\use:c {@kivi@infobox\l_keys_choice_tl}},
+ infobox .default:n = true,
+ infobox .initial:n = true,
+ reffields .meta:n = {infobox=false},
+ footer .choices:nn = {true,false} {\use:c {@kivi@footer\l_keys_choice_tl}},
+ footer .default:n = true,
+ footer .initial:n = true,
+ nofooter .meta:n = {footer=false},
+ unknown .code:n = \PassOptionsToPackage{\l_keys_key_str=#1}{scrletter},
+}
+\ExplSyntaxOff