what is "${distro_id}ESM:${distro_codename}" in unattended-upgrades config?

I wonder what

"${distro_id}ESM:${distro_codename}";

is in the 50unattended-upgrades file. It was enabled by default for me (after enabeling unattended-upgrades package at least.) Right now I disabled it and only have -security enabled for automatic upgrades but I would like to understand what it is and whether it would be good to uncomment that line again.

Here is the block it's in;

Unattended-Upgrade::Allowed-Origins {  //   
"${distro_id}:${distro_codename}";
         "${distro_id}:${distro_codename}-security";  
         // Extended Security Maintenance; doesn't necessarily exist for  
         // every release and this system may not have it installed, but if  
         // available, the policy for updates is such that unattended-upgrades  
         // should also install from here by default.       
 // "${distro_id}ESM:${distro_codename}";    
// "${distro_id}:${distro_codename}-updates";     
// "${distro_id}:${distro_codename}-proposed";     
// "${distro_id}:${distro_codename}-backports";   
};

Is it some sort of mother that should be enabled before I can enable the -updates, -proposed, -backports?

Thanks a lot.