Additional fixes

src/background/background.js

@@ -315,7 +315,8 @@ function originFromHost(host) {
 }
 
 // Read the `Referer` request header (the browser may title-case it; the
-// `extraHeaders` option exposes it to MV3 onBeforeSendHeaders).
+ // (onBeforeSendHeaders cannot read request headers in MV3 without a blocking API,
+ // so we fall back to the page origin for hosts that send no referer).
 function readReferer(headers) {
   if (!Array.isArray(headers)) return '';
   for (const h of headers) {
@@ -385,7 +386,7 @@ chrome.webRequest.onBeforeSendHeaders.addListener(
       await persistReferer(host, originFromHost(host));
       }
    },
-{ urls: ['<all_urls>'], extraHeaders: ['Referer'] }
+{ urls: ['<all_urls>'] }
 );
 
 // Install (idempotently) a DNR rule that sets the captured referer for a given