This is an article talking about minecrafts 15th year anniversary and what you could do / find.
Here are some other minecraft related articles:
Website homepage
here you can mine the background and find 2 chests.
The chests contain:
With Minecraft Classic, you can play minecraft classic here
And with the Partnerships & Celebrations Wallpapers you have 3 buttons:
Clicking any of these will download a zip.
Redeemables
on https://www.minecraft.net/en-us/redeem you can redeem a lot of things. For example: get a cape when watching 15 minutes of twitch streams.