WPT already records the video of Lighthouse working its magic but a couple of things need to be done on our side to make processing possible since we're mostly a blackbox.

• Support custom blank pages per pass through config (feat: configurable blank page options #1732)
• Support custom blank page hold durations per pass through config (feat: configurable blank page options #1732)
• Support config extensions (feat: allow extension of default config #1731)