If you want to get technical, it's the Microsoft Book "category" of their store.
Here's a snippet from
https://support.microsoft.com/en-us/...soft-store-faq:
The books category is closing
Starting April 2, 2019, the books category in Microsoft Store will be closing. Unfortunately, this means that starting July 2019 your ebooks will no longer be available to read, but you'll get a full refund for all book purchases. See below for details.
While you can no longer purchase or acquire additional books from the Microsoft Store, you can continue to read your books until
July 2019 when refunds will be processed.
Will I be able to buy, rent or pre-order books after April 2, 2019?
No. On April 2, 2019, you can no longer buy, rent or pre-order books. You can continue to use Microsoft Edge to read books you've acquired until early July 2019.
What happens to books I've pre-ordered with delivery after April 2, 2019?
Your pre-order will be cancelled, and you will not be charged for the purchase. We recommend you pre-order at another digital book store.
That's the snippet--more information is available at
the Microsoft webpage cited above.
I didn't even know that Microsoft had an ebook store. Maybe if they had done more to promote it, it could have stayed in business.
I suppose that if you had, or still have, any ebooks with the Microsoft Store, you already knew of this development. But perhaps not. The date to keep in mind, now, is in
early July 2019, when you will no longer be able to read your ebooks (at all, apparently) and Microsoft
will issue refunds to you for the ebooks that you have purchased.
Kudos to Microsoft for
not being like some ebook stores that we know but, instead,
refunding the price that purchasers paid for the ebooks! My estimation of Microsoft has gone up several notches.
