The image is based on Debian Buster, since we want an older Linux distribution (Buster has long-term support into 2024) to build binaries that are as portable as possible.
If you're running on a machine that has an ARM chip (Apple M1/M2, etc.), add `--platform linux/amd64` to the `docker build` command. It can take approximately four hours for an initial build to complete. Due to caching, subsequent builds take less time (~10 mins or so).