diff --git a/doc/03-cli.md b/doc/03-cli.md
index 340d2f299..4996c2205 100644
--- a/doc/03-cli.md
+++ b/doc/03-cli.md
@@ -858,10 +858,6 @@ This env var controls the [`discard-changes`](06-config.md#discard-changes) conf
 If set to 1, this env var will make Composer behave as if you passed the
 `--no-interaction` flag to every command. This can be set on build boxes/CI.
 
-### COMPOSER_DISABLE_XDEBUG_WARN
-
-If set to 1, this env disables the warning about having xdebug enabled.
-
 ### COMPOSER_ALLOW_SUPERUSER
 
 If set to 1, this env disables the warning about running commands as root/super user.