Snapcraft

Add /snap/bin to path.

itsfoss.com/ Complete Guide for Using Snap Packages In Ubuntu and Other Linux Distributions

        sudo apt install snapd
        
        To find Snap packages in the terminal, use the following command:
        snap find search-text
        
        sudo snap install pkg-name
        

snapcraft.io/ Firefox

        sudo apt remove firefox-esr iceweasel
        

snapd not available in Debian 8

        lsb_release -a
         ...
        Distributor ID:	Debian
        Description:	Debian GNU/Linux 8.11 (jessie)
        Release:	8.11
        Codename:	jessie