Action may force a page redirect by returning an object with $redirect property:

return {
    $redirect: ...
}

This especially is useful in (isolated) module controllers.

Currently $redirect must be a Map with special (undocumented) keys and values.

This is more complicated as it should be. We now allow $redirect to be a string that ist used as redirect URL:

return {
    $redirect: context("name:home").contenturl()
}

This now is similar to WGA.redirectTo(...)