iMicknl/ha-nest-protect: Nest Protect integration for Home Assistant (github.com)
A first, initial and very limited version to try. It should work for Nest Protect devices with Google Accounts, hasn’t been tested with Nest Protect Battery versions. See known limitations and issues for the current state of the project.
If you would like to test, that would be great. Please report any issues or bugs via GitHub Issues.