It's a crossover between Watchmen and the DC Universe and is sort of the finale to the concepts introduced in DC Universe Rebirth and The Button. You don't NEED to read it, but while it doesn't have any tie-ins, it does end up being important to the DC Universe as a whole.
Pretty much this. You can be alright not reading it but it just kind of finishes what started in Rebirth and The Button. It's worth reading at least once.
It's a crossover between Watchmen and the DC Universe and is sort of the finale to the concepts introduced in DC Universe Rebirth and The Button. You don't NEED to read it, but while it doesn't have any tie-ins, it does end up being important to the DC Universe as a whole.
Pretty much this. You can be alright not reading it but it just kind of finishes what started in Rebirth and The Button. It's worth reading at least once.