This method is only available in the Debug Build of Phaser, or a build with the
WEBGL_DEBUG flag set in the Webpack Config.
Phaser v3.60 Debug has a build of Spector.js embedded in it, which is a WebGL inspector that allows for live inspection of your WebGL calls. Although it's easy to add the Spector extension to a desktop browsr, by embedding it in Phaser we can make it available in mobile browsers too, making it a powerful tool for debugging WebGL games on mobile devices where extensions are not permitted.
See https://github.com/BabylonJS/Spector.js for more details.
This method will capture the next WebGL frame and send it to the Spector.js tool for inspection.