Welcome! In order to view your likes, Tumblr requires that you first log in and provide access for this "application" (it's really just one page). This allows the page to make queries against Tumblr's API for your likes and other user information.
The information is only used for presentation and
is not stored anywhere or used for any reason other than to
display your likes.
With that being said...sign in with Tumblr to continue!