diff --git a/sig/_polyfill/rails.rbs b/sig/_polyfill/rails.rbs
new file mode 100644
index 0000000..9c76415
--- /dev/null
+++ b/sig/_polyfill/rails.rbs
@@ -0,0 +1,3 @@
+module Rails
+  def self.backtrace_cleaner: () -> untyped
+end
diff --git a/sig/polyfill.rbs b/sig/interfaces.rbs
similarity index 82%
rename from sig/polyfill.rbs
rename to sig/interfaces.rbs
index 6a314c4..a25fe53 100644
--- a/sig/polyfill.rbs
+++ b/sig/interfaces.rbs
@@ -1,7 +1,3 @@
-module Rails
-  def self.backtrace_cleaner: () -> untyped
-end
-
 module ActiveRecord::Originator
   interface _ArelVisitor
     def accept: (untyped, untyped) -> untyped