Google Chrome was the primary driver and adopter of the Pepper Flash architecture. Beginning with Chrome version 21, Google integrated Pepper Flash directly into the browser, eliminating the need for users to manually install or update the plugin. This "bundled" approach significantly improved security, as Chrome could automatically update the Flash component alongside the browser engine.
The legacy NPAPI architecture dated back to the mid-1990s. It ran plugins as shared libraries within the main browser process. As browsers moved toward multi-process models (separating the UI from web rendering) to prevent crashes, NPAPI plugins became a bottleneck. They frequently caused the entire browser to crash if the plugin failed, and they lacked native support for modern sandboxing security features. pepper flash player download