Checksums added to assets
As of the 2020-10 REST API, checksums will be provided on assets that were recently updated.
If you use a client that supports checksums (ie Theme Kit 1.1 or newer), then the time it will take to sync your local files and the bandwidth used will be drastically reduced.
For more information, please see the checksum field in the REST API.
Please also see the blog post: How We Improved Theme Development Tooling Using Checksums