config/debian/external-signatures.conf

 External-Signature-Requests {
   Sources {
-    // fwupdate {
-    // };
+    fwupdate {
+      Packages {
+        "fwupdate-amd64-signed-template";
+        "fwupdate-arm64-signed-template";
+        "fwupdate-armhf-signed-template";
+        "fwupdate-i386-signed-template";
+      };
+      Architectures {
+        "amd64"; "arm64"; "armhf"; "i386";
+      };
+    };
     // grub2 {
     // };
     linux {