diff --git a/ext/bg/js/request-builder.js b/ext/bg/js/request-builder.js
index 011d6bb8..e4380734 100644
--- a/ext/bg/js/request-builder.js
+++ b/ext/bg/js/request-builder.js
@@ -27,10 +27,12 @@ class RequestBuilder {
             ['cookie', null],
             ['origin', {name: 'Origin', value: originURL}]
         ];
-        return this.fetchModifyHeaders(url, init, modifications);
+        return await this._fetchModifyHeaders(url, init, modifications);
     }
 
-    async fetchModifyHeaders(url, init, modifications) {
+    // Private
+
+    async _fetchModifyHeaders(url, init, modifications) {
         const matchURL = this._getMatchURL(url);
 
         let done = false;
@@ -68,8 +70,6 @@ class RequestBuilder {
         }
     }
 
-    // Private
-
     _onBeforeSendHeadersAddListener(callback, filter) {
         const extraInfoSpec = this._onBeforeSendHeadersExtraInfoSpec;
         for (let i = 0; i < 2; ++i) {