X-Large viewport
1440 and larger
X-Large viewport
1440 and larger

Columns: 24
Gutter width: 40px
Margin (left and right): 150px
Large viewport
1280 - 1439
Large viewport
1280 - 1439

Columns: 24
Gutter width: 40px
Margin (left and right): 128px
Medium viewport
1024 - 1279
Medium viewport
1024 - 1279

Columns: 24
Gutter width: 24px
Margin (left and right): 84px
Small viewport
768 - 1023
Small viewport
768 - 1023

Columns: 24
Gutter width: 20px
Margin (left and right): 68px
X-Small viewport
767 and smaller
X-Small viewport
767 and smaller

Columns: 12
Gutter width: 20px
Margin (left and right): 40px
How it works
The viewports cater to standard screen sizes for smartphones, tablets, notebooks and desktop PCs.
Depending on the available window size, the page layout displays the available content modules or containers in a different order or size. Up to a window width of 1440 pixels the layout takes the full window.
The XL view must be enabled in the site properties. Otherwise, the pages of a site will be displayed only up to the L-viewport.
Margin and gutter are fixed value, rows are flexible up to XL. On XL and above margin will increase, gutter and rows (content-width) are fixed.
Note
The display is driven by the available window size (viewport), not the device type.
Crosslinks
Reference for publisher

On the chrome-browser, clicking "F12", opens DevTools, where you can check responsiveness.