SAP Bank Accounting in S/4HANA: House Banks, Statements, and Fiori Apps
Book: Financial Accounting in SAP S/4HANA Finance Simplified: Questions & Answers by Narayanan Veeriah | ISBN 978-93-65898-675
Chapter 18 is a full chapter on bank accounting (questions 561 through 579). Not a sub-ledger like AR or AP. FI-BL is a sub-application for bank master data, payment processing, and reconciling what your bank says happened with what SAP recorded.