Canon C100, FCPX and Youtube 1440P Upload

Hello, I recently saw a youtube user using a Canon C100 upload to youtube above 1080p which is 1440p. Can someone explain exactly what 1440P is and how it works, also How can I upload to youtube in 1440?
Here is the video.

I think you just export your video at 2560x1440 and upload it.

From support.google.com/youtube/answer/172217...en&ref_topic=2888648
Resolutions

YouTube uses 16:9 aspect ratio players. If you are uploading a non-16:9 file, it will be processed and displayed correctly as well, with pillar boxes (black bars on the left and right) or letter boxes (black bars at the top and bottom) provided by the player. If you want to fit the player perfectly, encode at these resolutions:

2160p: 3840x2160
1440p: 2560x1440
1080p: 1920x1080
720p: 1280x720
480p: 854x480
360p: 640x360
240p: 426x240
The YouTube player automatically adds black bars so that videos are displayed correctly without cropping or stretching, no matter the size of the video or the player.