From their starting-page:

Powering current and next-generation map products by creating reliable, easy-to-use, and interoperable open map data

Overture is for developers who build map services or use geospatial data.

Some items from their FAQ:

What types of map data will Overture release?

Overture map data will evolve over time. Initially, we are focusing on layers for transportation, places, 3D buildings and administrative boundaries data. To support next-generation map products, Overture will steadily improve the coverage, resolution and accuracy of existing data. In addition, Overture will introduce new layers as the community prioritizes them.

What is the relationship between Overture and OpenStreetMap?

Overture is a data-centric map project, not a community of individual map editors. Therefore, Overture is intended to be complementary to OSM. We combine OSM with other sources to produce new open map data sets. Overture data will be available for use by the OpenStreetMap community under compatible open data licenses. Overture members are encouraged to contribute to OSM directly.

How will Overture data be licensed?

Generally, Overture data is licensed under the Community Database License Agreement – Permissive v2 (CDLA) unless derived from a source that requires publishing under a different license, such as data derived from OpenStreetMap, that constitutes a “Derivative Database” (as defined under ODbL v1.0), which will be licensed under ODbL v1.0.

When will Overture begin releasing datasets?

Overture will release its first datasets in the first half of 2023. We’re working through our plans and will share more details as soon as we’re ready.

Will Overture release open source code?

Overture will develop open source code to help developers process and effectively use Overture map data and the global entity reference system. Code will be available on GitHub.