diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 28285e00..1d6526d1 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -629,7 +629,7 @@ Lua:
 
 M:
   type: programming
-  lexer: Text only
+  lexer: common-lisp
   aliases:
   - mumps
   extensions: