Unity Addressables perm or temp assets?

So with the Addressables, if I make several Addressable bundles and pop on a webserver for example, The client loads, sees it needs Asset X so downloads from the webserver, does it retain it or only downloads to use then deletes? Like websites download and 'Cache' more or less what it downloads, and if it needs them later it just pulls of the hard drive if it has them already, but checks the site to see a new version/modified one exists and if so redownloads. Does the addressables work this way or is that more scripting to do to make it not keep downloading the same things over and over again? Also if it does, does it download the whole bundle or just the changed asset? Like I have a bundle with 100 materials and textures, change one, does it just update that one or redownload the whole pack?