Ecosia and Qwant join forces to develop European search index - Better Web
betterweb.qwant.com
Ecosia and Qwant today reveal a new joint venture, European Search Perspective (EUSP), to develop and build search engine infrastructure in Europe. EUSP aims to contribute to digital sovereignty within Europe and ensure the continent has a strong, independent alternative to existing search technologies.

Historically, they have both been relying mostly on the Bing index, with Qwant building its own index for a while and serving a mix.