diff --git a/src/syntax_mapping/builtins/99-unset-ambiguous-extensions.toml b/src/syntax_mapping/builtins/99-unset-ambiguous-extensions.toml
new file mode 100644
index 00000000..53800211
--- /dev/null
+++ b/src/syntax_mapping/builtins/99-unset-ambiguous-extensions.toml
@@ -0,0 +1,4 @@
+[mappings]
+"MappingTarget::MapExtensionToUnknown" = [
+    "*.conf",
+]