→ JavaScript objects do not contain single or double quote marks around the keys when no spacing is used in the key name. So, if there’s spacing in the key name, quotes are used. An Example is given below:
var person= {first name: “Depp”, address: “earth”}; **//invalid** // **To prevent this error:**
var person= {“first name”: “Depp”, "address": “earth”};
Based on your guess, I did another small test.
Even I type quotes for c property, it doesn’t show quotes later. So my guess is that the browser adds quotes to variables with spaces for better Readability. And a good practice is to use camelCase!