Document config.cli.php

content/docs/1_guide/12_configuration/guide.txt

@@ -174,6 +174,18 @@ Note that the settings in the standard `config.php` file are always used. If you
 General settings for all environments should be included in the standard `config.php` file to avoid code duplication. 
 </info>
 
+<since v="3.9.8">
+### CLI configuration
+
+If you are using Kirby with a command-line interface (or CLI for short), for example with the (link: plugins/getkirby/cli text: Kirby CLI) or with a custom script, you can define specific config overrides in a separate file:
+
+```filesystem
+/site/config/config.cli.php
+```
+
+The CLI-specific config file works like a host-specific config file in that it can override anything you put into your standard `config.php`.
+</since>
+
 ### Deployment configuration
 
 There is another optional config file that overrides any option value, no matter if it was set in `config.php` or a host-specific config file: