diff --git a/packages/playwright-core/browsers.json b/packages/playwright-core/browsers.json
index 56d4a2bbbc98c..3ac1c3e0b2e37 100644
--- a/packages/playwright-core/browsers.json
+++ b/packages/playwright-core/browsers.json
@@ -31,7 +31,7 @@
     },
     {
       "name": "firefox",
-      "revision": "1515",
+      "revision": "1518",
       "installByDefault": true,
       "browserVersion": "149.0",
       "title": "Firefox"
diff --git a/packages/playwright-core/src/server/firefox/protocol.d.ts b/packages/playwright-core/src/server/firefox/protocol.d.ts
index d0cbb465a52f6..6e0822b91e849 100644
--- a/packages/playwright-core/src/server/firefox/protocol.d.ts
+++ b/packages/playwright-core/src/server/firefox/protocol.d.ts
@@ -520,6 +520,7 @@ export namespace Protocol {
         width: number;
         height: number;
       }|null;
+      deviceScaleFactor?: number;
     };
     export type setViewportSizeReturnValue = void;
     export type setZoomParameters = {