Breaking: #72474 - RequestHandler only works with Routes

See Issue #72474

Description

The default backend RequestHandler had a fallback that triggered the backend initialization without having a &route= request parameter set. This was used for the transition when deprecating the traditional entry-scripts. The logic has been removed.

Impact

Any regular backend request (non-module and non-AJAX) will now require a &route= request parameter, otherwise will fallback to the default route (login) when not provided.

Migration

For all backend-related calls, either use a custom RequestHandler or switch to Backend Routing.