alt Hacker NewsGuess: same icon used in very small size for lists/menus and much larger when you select the item. Also, if the same one is used for all resolutions, the actual size can vary widely between monitor sizes, DPIs, resolutions, scales. Good to have one that looks decent to people who see it large and/or care about quality
Pretty much.
The icon appeared bigger in some places than others and wanted it to look decent on higher DPI displays.
SVGs are so much better for this though, smaller in size and look great at pretty much any resolution.