  Websites are capable of learning a wide range of information about the
platform on which a browser is executing. One major source of such information
is the set of standardised Application Programming Interfaces (APIs) provided
within the browser, which can be accessed by JavaScript downloaded by a
website; this information can then either be used by the JavaScript or sent
back to the originating site. As has been widely discussed, much of this
information can threaten user privacy. The main purpose of this paper is to
document a publicly available platform designed to enable further investigation
of one class of such threats, namely those based on analysing user behavioural
data. The platform has two main components: a Chrome extension that gathers
user keystroke and mouse data via browser APIs, and server software that
collects and stores this data for subsequent experimentation.
