JSON Object Validator is installed

Click the puzzle piece (1) in the top right of your browser, then click the pin (2) next to the extension:

Chrome's extensions menu open, with the puzzle-piece button in the toolbar
marked 1 and the pin button beside JSON Object Validator marked 2

Now click the icon in your toolbar to open the panel on any page:

The orange JSON Object Validator icon pinned in the Chrome toolbar, with an
arrow pointing to it