diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index b485ca3317ed..e698aba81d55 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -30,7 +30,6 @@ variables:
   RUSTY_CACHIER_COMPRESSION_METHOD: zstd
   NEXTEST_FAILURE_OUTPUT: immediate-final
   NEXTEST_SUCCESS_OUTPUT: final
-  ZOMBIENET_IMAGE: "docker.io/paritytech/zombienet:v1.3.80"
   DOCKER_IMAGES_VERSION: "${CI_COMMIT_SHA}"
 
 default:
@@ -199,9 +198,6 @@ default:
     - if: $CI_COMMIT_REF_NAME =~ /^[0-9]+$/ # PRs
     - if: $CI_COMMIT_REF_NAME =~ /^gh-readonly-queue.*$/ # merge queues
 
-.zombienet-refs:
-  extends: .build-refs
-
 include:
   # check jobs
   - .gitlab/pipeline/check.yml
diff --git a/.gitlab/pipeline/zombienet.yml b/.gitlab/pipeline/zombienet.yml
index 64210d6a00ab..fc3fd1256194 100644
--- a/.gitlab/pipeline/zombienet.yml
+++ b/.gitlab/pipeline/zombienet.yml
@@ -1,3 +1,8 @@
+.zombienet-refs:
+  extends: .build-refs
+  variables:
+    ZOMBIENET_IMAGE: "docker.io/paritytech/zombienet:v1.3.82"
+
 include:
   # substrate tests
   - .gitlab/pipeline/zombienet/substrate.yml
diff --git a/.gitlab/pipeline/zombienet/substrate.yml b/.gitlab/pipeline/zombienet/substrate.yml
index 6334e7db9a32..b687576267de 100644
--- a/.gitlab/pipeline/zombienet/substrate.yml
+++ b/.gitlab/pipeline/zombienet/substrate.yml
@@ -40,14 +40,13 @@
   tags:
     - zombienet-polkadot-integration-test
 
-# Skip this one until PolkadotJS includes `SkipCheckIfFeeless` extension
-# zombienet-substrate-0000-block-building:
-#   extends:
-#     - .zombienet-substrate-common
-#   script:
-#     - /home/nonroot/zombie-net/scripts/ci/run-test-local-env-manager.sh
-#       --local-dir="${LOCAL_DIR}/0000-block-building"
-#       --test="block-building.zndsl"
+zombienet-substrate-0000-block-building:
+  extends:
+    - .zombienet-substrate-common
+  script:
+    - /home/nonroot/zombie-net/scripts/ci/run-test-local-env-manager.sh
+      --local-dir="${LOCAL_DIR}/0000-block-building"
+      --test="block-building.zndsl"
 
 zombienet-substrate-0001-basic-warp-sync:
   extends:
diff --git a/substrate/frame/transaction-payment/skip-feeless-payment/src/lib.rs b/substrate/frame/transaction-payment/skip-feeless-payment/src/lib.rs
index 923c7e7ebc29..55afaaf93d78 100644
--- a/substrate/frame/transaction-payment/skip-feeless-payment/src/lib.rs
+++ b/substrate/frame/transaction-payment/skip-feeless-payment/src/lib.rs
@@ -77,9 +77,9 @@ pub mod pallet {
 /// A [`SignedExtension`] that skips the wrapped extension if the dispatchable is feeless.
 #[derive(Encode, Decode, Clone, Eq, PartialEq, TypeInfo)]
 #[scale_info(skip_type_params(T))]
-pub struct SkipCheckIfFeeless<T: Config, S: SignedExtension>(pub S, sp_std::marker::PhantomData<T>);
+pub struct SkipCheckIfFeeless<T, S>(pub S, sp_std::marker::PhantomData<T>);
 
-impl<T: Config, S: SignedExtension> sp_std::fmt::Debug for SkipCheckIfFeeless<T, S> {
+impl<T, S: Encode> sp_std::fmt::Debug for SkipCheckIfFeeless<T, S> {
 	#[cfg(feature = "std")]
 	fn fmt(&self, f: &mut sp_std::fmt::Formatter) -> sp_std::fmt::Result {
 		write!(f, "SkipCheckIfFeeless<{:?}>", self.0.encode())
@@ -90,9 +90,8 @@ impl<T: Config, S: SignedExtension> sp_std::fmt::Debug for SkipCheckIfFeeless<T,
 	}
 }
 
-impl<T: Config + Send + Sync, S: SignedExtension> SkipCheckIfFeeless<T, S> {
-	/// utility constructor. Used only in client/factory code.
-	pub fn from(s: S) -> Self {
+impl<T, S> From<S> for SkipCheckIfFeeless<T, S> {
+	fn from(s: S) -> Self {
 		Self(s, sp_std::marker::PhantomData)
 	}
 }
@@ -106,7 +105,11 @@ where
 	type Call = S::Call;
 	type AdditionalSigned = S::AdditionalSigned;
 	type Pre = (Self::AccountId, Option<<S as SignedExtension>::Pre>);
-	const IDENTIFIER: &'static str = "SkipCheckIfFeeless";
+	// From the outside this extension should be "invisible", because it just extends the wrapped
+	// extension with an extra check in `pre_dispatch` and `post_dispatch`. Thus, we should forward
+	// the identifier of the wrapped extension to let wallets see this extension as it would only be
+	// the wrapped extension itself.
+	const IDENTIFIER: &'static str = S::IDENTIFIER;
 
 	fn additional_signed(&self) -> Result<Self::AdditionalSigned, TransactionValidityError> {
 		self.0.additional_signed()