How to setup the root cert for dummies, by renge

Do you want to access everything like nothing is different? Do you trust this dumb person on the Internet to not misuse this against you? Good! Then here is how to do it, based on how you are visiting.

For all of these, you will want to download the root.crt, which you will then install into your device based on the instructions. If you're concerned about your security for doing this (that's good), feel free to look up what this entails, or ask your tsundere AI friend with web lookup or something.

Firefox (any device)

~~Due to Firefox being different, you need to install the root CA inside of it, regardless of if it's in your system store.~~

So apparently, Firefox is no longer different on Windows, macOS and Android, so feel free to ignore this. If you do have issues, do follow it though.

Open your Firefox settings (Menu -> Settings, or go to about:preferences)
Privacy and Security -> Advanced settings (at the bottom) -> Manage certificates (at the bottom) -> Import... -> select root.crt -> for websites, import

Windows

Double click on root.crt.
Select Import Certificate.
On the Certificate Store page, select Place all certificates in the following store and click Browse. There, select Show Physical Stores and double click on Trusted Root Certification Authorities. Select Local Computer, then click OK.
Click Next and Finish. You should be done!

Android

Android is.. complicated. To avoid MITM attacks, most apps ignore user-installed certificates, so you should follow your browsers instructions. If unclear, contact me and I'll try to help you. If you have a rooted device or something, this is how you do it.

Open your device's settings, find the Security tab, and Manage certificates. Then look for something like "Install from SD card/internal storage."
Select root.crt, and install for apps and websites, NOT WiFi and VPN.
..that's it! If you're rooted, you should be able to find how to install into the system store, which will work around anything.

Linux

Every distro is different, and this might not work for you. You're on Linux, so you should be capable of looking up instructions specific to your setup. But.. you can also contact me.

Here are some instructions primarily targeting Debian-based distros, incl. Ubuntu and Linux Mint.

Get sudo or root.
sudo mkdir /usr/local/share/ca-certificates/rengeca
cd [whatever directory you downloaded root.crt to]
sudo cp root.crt /usr/local/share/ca-certificates/rengeca/
sudo update-ca-certificates

iOS/iPadOS

Unlike Android, iOS apps respect user-installed certs, making this much easier!

Though, I heard they need a specific format. I can't test it right now, but if you have troubles, contact me.

When downloading root.crt, you should get some kind of popup to install a profile. Do so. (You might have to go to Settings to confirm)
Enable the profile. Also go to [Settings > General > About > Certificate Trust Settings], and enable RengeCA.