[bastawhiz]

It depends on a few things. With the "fusion" style, the basic widgets look good, but they look kind of off—definitely not native. Some widgets seem to have received little attention, like the calendar widget. The classic "rectangle with a dark to light gray gradient" button is a good giveaway. Dropdowns where the text doesn't get centered. Steppers next to text inputs that are the wrong size. Focus rings that are in the wrong place (compared to native counterparts).

Electron, at the very least, has Chromium inputs by default, which are arguably about as close to the native equivalents that you can get. Developers almost always restyle them, but you can't fault Electron for that.