Data governance covers the arrangements and systems that make data findable, understandable and trustworthy: data catalogues, data lineage, data quality checks, ownership and master data management (MDM). Organisations use it to know which data lives where, who is responsible for it, and which version of a customer or product record is authoritative. Informatica is a well-known non-European reference point.
A catalogue is rarely where data is stored, but it is the map showing where everything is. To fill that map the tool needs connections to nearly all your source systems, with the credentials that go with them. The lasting value is then in glossaries, lineage graphs and quality rules that hold years of accumulated knowledge, often in a proprietary model. That makes switching expensive. With MDM the system also manages the golden records other applications rely on. The Data Act promotes open interfaces and interoperability between data processing services, which can serve as a yardstick here.
When choosing a European option, look for open metadata and lineage standards, a complete API for exporting catalogue and glossary, local connectors that keep credentials inside your own network, and a clear separation between metadata and the content of source systems.