NOTE Chrome (running 48.x) is aware of syntax-suffixes and displays content inline, thus this extension is redundant.
Treat responses with Content-Type suffixed with +json and +xml as inline documents.
If you are trying out some GET HTTP requests in your browser against an API that uses vendor Content-Types that adhere to Structured Syntax Suffixes, then it is annoying to have them downloaded, instead of showing them inline.
I myself prefer vendor Content-Types, against the "profile" link. This browser extension just makes things a tad easier, not more "right".
You can install it from Chrome Web Store https://chrome.google.com/webstore/detail/cgfnklamhhieaepdicnbahkbnolpbdmp.
Or run make install and follow the instructions.