From the look of this
announcement from the White House, there appear to be two components. The first one, free preschool, is detailed in the post above. The other, affordable child care, is explained here:
The Build Back Better framework will ensure that the vast majority of working American families of four earning less than $300,000 per year will pay no more than 7 percent of their income on child care for children under 6. Parents who are working, looking for work, participating in an education or training program, and who are making under 2.5 times their states median income will receive support to cover the cost of quality care based on a sliding scale, capped at 7% of their income.
I'm not sure how this interacts with the existing Child and Dependent Care Credit. Maybe it replaces it? The devil is in the details, and I'm hungry for details!