This configuration does not include some hardening configurations, as those are maintained [here](https://github.com/tommytran732/Linux-Setup-Scripts/blob/main/Ubuntu-22.04-Server.sh).
- Systemd overrides for NGINX and SSHD services are based on [GrapheneOS's configurations](https://github.com/GrapheneOS/infrastructure/tree/main/systemd/system).
- Systemd override for Synapse is based on Arch Linux's [matrix-synapse](https://gitlab.archlinux.org/archlinux/packaging/packages/matrix-synapse/-/blob/main/override-hardened.conf?ref_type=heads) package.
- The repolists of PostgreSQL and Docker have been modified so that they read GPG keys from `/usr/share/keyring` by default. Make sure that when you follow upstream's documentation on adding their GPG keys, you adjust the location. For PostgreSQL's GPG key, run `curl https://www.postgresql.org/media/keys/ACCC4CF8.asc | gpg --dearmor | sudo tee /usr/share/keyrings/postgresql-debian-repo.gpg >/dev/null`