diff --git a/dev/setup/codesniffer/ruleset.xml b/dev/setup/codesniffer/ruleset.xml
index daf73e5b2a7..89ea98a051b 100644
--- a/dev/setup/codesniffer/ruleset.xml
+++ b/dev/setup/codesniffer/ruleset.xml
@@ -6,6 +6,7 @@
 	<exclude-pattern type="relative">build/html</exclude-pattern>
 	<exclude-pattern type="relative">build/aps</exclude-pattern>
 	<exclude-pattern type="relative">documents</exclude-pattern>
+	<exclude-pattern type="relative">htdocs/core/class/lessc.class.php</exclude-pattern>
 	<exclude-pattern type="relative">htdocs/custom</exclude-pattern>
 	<exclude-pattern type="relative">htdocs/includes</exclude-pattern>
 	<exclude-pattern type="relative">htdocs/install/doctemplates/websites</exclude-pattern>