DevKit7 (pkg.npid7.de)

Setup

At first, you need the Public key. To get it, simply run the folowing

Download Public Key 
wget https://pkg.npid7.de/pubkey.asc
gpg --import pubkey.asc 
gpg --lsign-key 3166D283DA78C231
pacman-key --add pubkey.asc
pacman-key --lsign-key 3166D283DA78C231

On debian based systems you probably want to use Devkitpro's dkp-pacman

Note that you need sudo on linux / mac and you need to use Msys2 Terminal on Windows.

Open the pacman.conf in an editor like nano

sudo nano /etc/pacman.conf

Add the folowing to the Bottom of the Config (depending on your system)

Windows

Architectures: x86_64

[devkit7]
Server = https://pkg.npid7.de/windows/$arch

Linux

Architectures: aarch64, x86_64

[devkit7]
Server = https://pkg.npid7.de/linux/$arch

MacOS

Architectures: arm64, x86_64

[devkit7]
Server = https://pkg.npid7.de/osx/$arch

Test

Let's download makerom and bannertool as example:

pacman -Sy makerom bannertool