WPT details: WebGPU/WGSL have a conformance test suite (https://github.com/gpuweb/cts) that is regularly pulled into Chromium and part of the testing of Dawn/Tint in Chromium. Note that tests are still being written, but the feature will not be launched until it is fully tested.
Functionality added to the WebGPU/WGSL spec after its first shipment in a browser. Adds support for (read-only and) read-write storage textures which allow more general access to texture memory for GPU computation and can unlock more advanced graphical algorithms. This feature has been request by developers very often.