Comment 3 for bug 896639

Matt, it's highly unlikely that Gwibber would be using t.co. As far as I know that is a private service created and exclusively used by Twitter.

Gwibber shows your tweets as downloaded from Twitter, not as you posted them, and Twitter unfortunately shortens every link using their own link shortener, whether you want it to or not, and whether it actually becomes shorter or not.

The behaviour I am seeing is that as soon as I paste a link into Gwibber, it gets shortened (using is.gd, in my case), so before it is even posted.