I work as a BA within a team that predominantly works on Data Integration activities. We have a vendor system, into which we load different types of data, from a variety of sources. We validate the data and create a golden copy. We export data from it, with differing content and formats, it to a variety of target systems.
Traditionally the BA’s have written mapping documents (using Excel) to describe the data import/export requirements. These documents are fairly tightly controlled and aligned to the software release versions.