I will stick to the "clearly false" since it is now well to the point where we are in 2019-05-04 (even in local UT1, let alone UTC), studies are disabled (and have been since forever), no studies have been loaded, and my extensions still work quite fine, thank-you. Attempting to install a "new" extension fails with a "bad signature" error.
Here's something interesting - a few times now, I've told Firefox to enable Studies and then restarted ... but the Studies setting reverted to being unchecked.
Maybe one of my other paranoia-enabling extensions is toggling it off ... but if so, I haven't found it yet. Still investigating.
Royce