diff --git a/background/storage.js b/background/storage.js
deleted file mode 100644
index e7a1153f..00000000
--- a/background/storage.js
+++ /dev/null
@@ -1,30 +0,0 @@
-/* exported calcStyleDigest detectSloppyRegexps */
-'use strict';
-
-function normalizeStyleSections({sections}) {
-  // retain known properties in an arbitrarily predefined order
-  return (sections || []).map(section => ({
-    code: section.code || '',
-    urls: section.urls || [],
-    urlPrefixes: section.urlPrefixes || [],
-    domains: section.domains || [],
-    regexps: section.regexps || [],
-  }));
-}
-
-function calcStyleDigest(style) {
-  const jsonString = style.usercssData ?
-    style.sourceCode : JSON.stringify(normalizeStyleSections(style));
-  const text = new TextEncoder('utf-8').encode(jsonString);
-  return crypto.subtle.digest('SHA-1', text).then(hex);
-
-  function hex(buffer) {
-    const parts = [];
-    const PAD8 = '00000000';
-    const view = new DataView(buffer);
-    for (let i = 0; i < view.byteLength; i += 4) {
-      parts.push((PAD8 + view.getUint32(i).toString(16)).slice(-8));
-    }
-    return parts.join('');
-  }
-}
diff --git a/js/sections-util.js b/js/sections-util.js
index 79413a7c..71ffabbe 100644
--- a/js/sections-util.js
+++ b/js/sections-util.js
@@ -1,4 +1,4 @@
-/* exported styleSectionsEqual styleCodeEmpty */
+/* exported styleSectionsEqual styleCodeEmpty calcStyleDigest */
 'use strict';
 
 function styleCodeEmpty(code) {
@@ -65,3 +65,31 @@ function styleSectionsEqual(a, b, {ignoreCode, checkSource} = {}) {
     );
   }
 }
+
+function normalizeStyleSections({sections}) {
+  // retain known properties in an arbitrarily predefined order
+  return (sections || []).map(section => ({
+    code: section.code || '',
+    urls: section.urls || [],
+    urlPrefixes: section.urlPrefixes || [],
+    domains: section.domains || [],
+    regexps: section.regexps || [],
+  }));
+}
+
+function calcStyleDigest(style) {
+  const jsonString = style.usercssData ?
+    style.sourceCode : JSON.stringify(normalizeStyleSections(style));
+  const text = new TextEncoder('utf-8').encode(jsonString);
+  return crypto.subtle.digest('SHA-1', text).then(hex);
+
+  function hex(buffer) {
+    const parts = [];
+    const PAD8 = '00000000';
+    const view = new DataView(buffer);
+    for (let i = 0; i < view.byteLength; i += 4) {
+      parts.push((PAD8 + view.getUint32(i).toString(16)).slice(-8));
+    }
+    return parts.join('');
+  }
+}