Delta Lake is an open-source storage framework for building a lakehouse architecture. It adds ACID transactions with serialisability to data lakes, with scalable metadata for very large tables, time travel to earlier versions, unified batch and streaming, schema enforcement and evolution, and an audit history. Delta Lake works with engines including Spark, Trino, Flink, PrestoDB and Hive. It is a software layer you deploy yourself, not a hosted service.
According to its website, Delta Lake is an independent project that is not controlled by any single company. It has been part of the Linux Foundation since 2019 and follows a published charter; the code is licensed under the Apache License 2.0. Because you run the layer yourself, you decide where the data resides: in your own data centre or with a European storage and cloud provider. The open format and open source code limit lock-in, including when commercial platforms offer their own implementation.