The MusicBrainz API page is currently not viewable on non-maximized windows or mobile devices because the text overflows off the screen.  See the image below.

 

The culprit is the following CSS:

• body { min-width: 780px }
• #page { display: table }
• #content { display: table-cell }

Removing these CSS properties (e.g. in the Chrome inspector) makes the text wrap nicely, as expected.