> Which email metadata program specifically
There was only one in the leaks. That one.
> how do you know there's no other programs
If there were any, Snowden would have leaked those instead of a program that had already been shut down.
> how do we know it actually was reduced and not just changed codename?
Because laws were changed, and oversight was added that showed how many metadata records the NSA requested from the telcos.
> how you know Biden personally had anything to do with shutting it down
Does it matter if he was personally in charge or if he delegated? Collection of Americans'metadata shrunk while he was VP.