first commit

dist/firefox/background.firefox.js

@@ -0,0 +1,29 @@
+const WINDOWS_UA = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.7444.163 Safari/537.36';
+
+browser.webRequest.onBeforeSendHeaders.addListener(
+  (details) => {
+    const headers = details.requestHeaders || [];
+    let found = false;
+
+    for (const header of headers) {
+      if (header.name && header.name.toLowerCase() === 'user-agent') {
+        header.value = WINDOWS_UA;
+        found = true;
+        break;
+      }
+    }
+
+    if (!found) {
+      headers.push({ name: 'User-Agent', value: WINDOWS_UA });
+    }
+
+    return { requestHeaders: headers };
+  },
+  {
+    urls: [
+      'https://figma.com/*',
+      'https://*.figma.com/*'
+    ]
+  },
+  ['blocking', 'requestHeaders']
+);