universe set
Set game keys: runner=dolphin proton=proton-em options.fullscreen=false capture.cursor=true hidden=true
Usage: universe set [OPTIONS] <NAME> [PAIRS]...Arguments
Section titled “Arguments”<NAME>: Game: exact id, then whole word, substring or path.[PAIRS]...: key=value; launch keys (universe launch-keys) need nolaunch.prefix, a runner option is options.<key>; the installed version is version.pin (said by hand), version.probe (@<file> or @<file>:<regex>, where the files hold it), version.switch_title_id, version.seen (the upstream build taken as installed), version.seen_installed (the version installed then) and version.final=true (no update flagged).