So how does triple licensed code work as an end user? They have multiple packages and i pick the one with the license i like? Or just one package and i just declare im using the AGPL 'essence' in my instance?
You have to buy a elasticsearch brand AGPL scented candle to light while you install the packages. If you aren't smelling their official blend of sandalwood, jasmine and developer blood, it reverts back to Elv2.
Either one of those, or it'll be one package and you choose the edition at install time, and it installs the appropriate features. (Or, if using a package manager, your distro will have the free one, and there will probably be a nonfree package available from the elastic site.)
There are also cases where it's the exact same code base, but purchasing a license allows you to do things that you otherwise couldn't (for AGPL, that would mean the ability to run a modified version of the code without making your modifications available to customers).