This API allows developers to get an estimation about the storage quota their Web app can use and is already using.
See https://www.chromestatus.com/features/5630353511284736 and https://storage.spec.whatwg.org/ for details.
Please prioritize this issue. Getting PWA consistently across all devices is very important to us as web developers. Thank you
+1 It will be fantastic to have this.
The Google Search team have just documented why they need the Storage Estimation API: https://web.dev/google-search-sw/#service-worker-overhead.