If you’re going to manipulate the DOM (typically via the dev console) it seems vanishingly unlikely you’d insert a new span with a different font rather than just overtyping the text.
You misunderstood. I am affirming, they have used Photoshop to insert text in that screenshot, and they have mistakenly used another font, Roboto. It's easily noticeable, as it's narrower, and some glyphs (like that "g") are different.