This project is based on Alpine Linux, the official nginx image and an nginx module that provides static and dynamic brotli compression. Brotli is built by Google. Originally this image used Google's nginx brotli module, though as it is no longer maintained I switched to eustas' fork.
As this project is based on the official nginx image look for instructions there. In addition to the standard configuration directives, you'll be able to use the brotli module specific ones, see here for official documentation
This image has support for Brotli and HTTP3 QUIC support (cdrocker/nginx:1.16.1) using Cloudflare quiche. Read more at https://github.com/cloudflare/quiche and https://blog.cloudflare.com/experiment-with-http-3-using-nginx-and-quiche/
Based on the work of fholzer/docker-nginx-brotli