Install the Chromium Deb package from Linux Mint Repository

First, create a file called mint.list as follows:

sudo vi /etc/apt/sources.list.d/mint.list

Add the following:

deb http://packages.linuxmint.com victoria upstream

download the latest Linux Mint Keys from:

http://packages.linuxmint.com/pool/main/l/linuxmint-keyring/?

Install the keyring deb file:

dpkg -i <FileName> or apt install <path to keyring deb file>

To stop Ubuntu from updating your system with Linux mint repositories, you need to define the priorities. Here, you only want to install and update the Chromium package from Linux Mint.

For this, create the preference file as follows:

vi /etc/apt/preferences.d/mint-victoria-pin

Insert following:

# Upgrade only Chromium from Linux Mint Victoria repository
Package: chromium
Pin: origin packages.linuxmint.com
Pin-Priority: 500

# Do not prefer other packages from the Linux Mint Victoria Repository
Package: *
Pin: origin packages.linuxmint.com
Pin-Priority: 1

Save this file and update your system.

sudo apt update

Now, you can install Chromium as a deb package from Linux Mint repositories.

sudo apt install chromium