When an AMPHTML ad is inside an non-AMP page context, it loads the entire AMP runtime. Although the AMP runtime is performant, it still has a lot of functionality that is irrelevant for rendering an ad. (e.g. scheduling)
This feature captures the effort to rewrite the AMP runtime in a way that's specifically catered for ads and in the process, reduce the ad runtime size to 50% that of the AMP runtime and also decrease ad render time. In addition, this feature will also include additional ad specific library compliance like SafeFrame and MRAID out of the box.