Feature: AJAX filters don't work

[MGatner]

Describe the bug
According to the User Guide on $methods in app/Config/Filters.php:

In addition to the standard HTTP methods, this also supports two special cases: ‘cli’, and ‘ajax’.

However, I cannot find anywhere in the code that would run AJAX filters. Method is set in system/Filters/Filters with no clause for AJAX:

$method = strtolower($_SERVER['REQUEST_METHOD'] ?? 'cli');
if (array_key_exists($method, $this->config->methods))

Unless I've missed something, I think this isn't implemented, and my test Filter is definitely not firing on AJAX calls.

CodeIgniter 4 version
Latest develop

Affected module(s)
Controller Filters

[jim-parry]

No mention of CLI or AJAX filters other than that one sentence in the user guide.
They make sense, and it sounds like they might have been planned, but overlooked in implementation :(
Something to add once stable :)