- * If you fail to call either [`ChannelManager::claim_funds`], [`ChannelManager::fail_htlc_backwards`],
- * or [`ChannelManager::fail_htlc_backwards_with_reason`] within the HTLC's timeout, the HTLC will be
- * automatically failed.
+ *
+ * If [`Event::PaymentClaimable::onion_fields`] is `Some`, and includes custom TLVs with even type
+ * numbers, you should use [`ChannelManager::fail_htlc_backwards_with_reason`] with
+ * [`FailureCode::InvalidOnionPayload`] if you fail to understand and handle the contents, or
+ * [`ChannelManager::claim_funds_with_known_custom_tlvs`] upon successful handling.
+ * If you don't intend to check for custom TLVs, you can simply use
+ * [`ChannelManager::claim_funds`], which will automatically fail back even custom TLVs.
+ *
+ * If you fail to call [`ChannelManager::claim_funds`],
+ * [`ChannelManager::claim_funds_with_known_custom_tlvs`],
+ * [`ChannelManager::fail_htlc_backwards`], or
+ * [`ChannelManager::fail_htlc_backwards_with_reason`] within the HTLC's timeout, the HTLC will
+ * be automatically failed.