And wherein a user "does not need to explicitly identify themselves".
Microsoft said the program creates the log file so a user does not have to download the same information repeatedly.
Indeed, among the first things that a user does at an intermediary's Web site is provide personal information.
These don't-track-me browser settings send out signals telling third parties that a user does not want to have his or her online activities tracked.
XKeyscore was previously described by former NSA-employer Edward Snowden as a tool that allows the agency to monitor "nearly everything a user does on the internet".
"If your account is public, blocking a user does not prevent that user from following you, interacting with your tweets, or receiving your updates in their timeline," an update on the Twitter website said.
They were surveilling world leaders, exploiting and hoarding software and hardware vulnerabilities in covert hacking operations, and intercepting phone data and "nearly everything a user does on the internet".
The device is essentially a touchscreen so sensitive that a user doesn't actually need to touch it.
Apps that a user doesn't want can be disabled from the launcher, stopping them from running and removing them from all but the phone's storage.
A user doesn't have to grip Mr. McKown's device because two wide hooks curl around the thumb and forefinger to fix it in place.
Even if a user doesn't fall for the login page trap, Fancy Bear can glean information from the click: the user's IP address and location, his or her browser type and version, and the target computer's operating system.
