config/debian/external-signatures.conf

 External-Signature-Requests {
   Sources {
+    fwupd {
+      Packages {
+        "fwupd-amd64-signed-template";
+        "fwupd-arm64-signed-template";
+        "fwupd-armhf-signed-template";
+        "fwupd-i386-signed-template";
+      };
+      Architectures {
+        "amd64"; "arm64"; "armhf"; "i386";
+      };
+    };
     fwupdate {
       Packages {
         "fwupdate-amd64-signed-template";
@@ -11,8 +22,16 @@ External-Signature-Requests {
         "amd64"; "arm64"; "armhf"; "i386";
       };
     };
-    // grub2 {
-    // };
+    grub2 {
+      Packages {
+        "grub-efi-amd64-signed-template";
+        "grub-efi-arm64-signed-template";
+        "grub-efi-ia32-signed-template";
+      };
+      Architectures {
+        "amd64"; "arm64"; "i386";
+      };
+    };
     linux {
       Packages {
         "linux-image-amd64-signed-template";