Does anyone, preferably from Cloudflare, know the settings used in D1, since it's a SQLite dialect?

D1 is built on Durable Objects, where SQLite is used on top of a custom distributed storage layer. This blog post describes in detail how the system works:

https://blog.cloudflare.com/sqlite-in-durable-objects/

In short, while we don't technically fsync, we do much better. If the local disk suddenly explodes, we won't lose confirmed writes.

(I wrote much of said storage layer.)

Is D1 a dialect? I thought they actually run SQLite.