When using SSL encryption, it's not possible for others to see which specific pages you visit, but they can still see which domains you browse to. At the moment, the DoH service is provided in cooperation with US-based Cloudflare, but this may change in the future.
Mozilla plans to enable DoH by default for all Firefox users. The company says they're pretty close to releasing this in the USA, this rollout is expected to start toward the end of September.
In 2017, Mozilla began working on the DNS-over-HTTPS (DoH) protocol, and since June 2018 we’ve been running experiments in Firefox to ensure the performance and user experience are great. We’ve also been surprised and excited by the more than 70,000 users who have already chosen on their own to explicitly enable DoH in Firefox Release edition. We are close to releasing DoH in the USA, and we have a few updates to share.More details can be read at Mozilla's blog. While the initiative has merits, not everyone is convinced this is a good move. By enabling this by default, it can cause issues for users and corporations that run their own DNS server. Some argue this is not a feature that should be handled by the browser, others argue it may result in slower browsing, and then there's also concern that Cloudflare is the only DNS resolver that this is compatible with (at this moment).