Vercel employs maybe half [correction, maybe a quarter] of the React core team. For example, at the keynote at React Conf 2025, it was mentioned that Andrew Clark, who, if I am not mistaken, is employed by Vercel, worked on resolving the rendering issue of React that was blocking the release of React 19 after it was discovered in the release candidate.

Vercel and Next.js have been the main testing ground during the development of React server components as well.

How much has Vercel contributed to the development of react over the past years?