authcacheFooter injection, some authcache information is not available at page build time. Luckily there is no need for the core authcache functions to run as late as possible, only the debug information must be collected at the very end of a page cycle.
As an extra benefit of this approach, we have better protection of the debug information because the AJAX phase is authenticated. Therefore the risk of leaking information via the cached
authcacheFooter is reduced.