We’re not sure why, but Borderlands: The Handsome Collection now appears to be available for free from the Microsoft Store
Simply follow this link, and click the ‘Get it Now’ button on the page. The game then should download automatically to your Xbox One if you’ve got automatic game downloads enabled.
The game includes a remastered version of Borderlands 2 and Borderlands: The Pre-Sequel.
Although the third game didn’t review quite as well as the first two, all three are still well worth a look, and this looks like a great way to get your hands on them.
We’ve received no official confirmation of whether this is a store bug or a promotion, so we’d suggest adding the game to your account sooner rather than later. NeoGaf is currently speculating that this is part of a free weekend promotion.