wagtail/client/scss/overrides/_utilities.focus.scss

// stylelint-disable declaration-no-important
// Set global focus outline styles so they are consistent across the UI,
// without individual components having to explicitly define focus styles.
// Using !important because we want to enforce only one style is used across the UI.
.focus-outline-on *:focus {
    outline: $focus-outline-width solid $color-focus-outline !important;
}

.focus-outline-off *:focus {
    outline: none !important;
}