The gray arrow down, is actually a ground connection symbol from electronics schematics notation. It symbolizes that the symbol is static.
If you move your mouse over these icons, there will be a small pop-up explaining the icon.
Within the editor control, you can also do Ctrl+Plus and Ctrl+Minus to increase/decrease the font size, respectively, if you want to zoom in and see a larger version of the icon for clarity. When there are multiple icons on the same line, they overlay with the highest priority icon being shifted up slightly, like a stack of cards.