Document jreleaser/jreleaser#1638

docs/modules/reference/pages/environment.adoc

@@ -393,3 +393,19 @@ Use the `env` command to display environment variable key names as resolved by t
  * xref:tools:jreleaser-ant.adoc#_jreleaser_env[{icon_ant_s} jreleaser-env]
 
 You'll also find  these key names in the respective `trace.log` file.
+
+== Magic Properties
+
+The value of the following properties may be resolved from an environment variable or a system
+property. The system property takes precedence over the environment variable.
+
+=== HTTP Logger
+
+Logs HTTP operations to the `trace.log` file.
+
+[horizontal]
+System Property:: jreleaser.feign.logger.level
+Environment Variable:: JRELEASER_FEIGN_LOGGER_LEVEL
+Default Value:: NONE
+Possible Values:: NONE, BASIC, HEADERS, FULL
+