Good branding is important for good extensions. As such, your extension icon is very important. A poorly designed icon, or an icon that doesn’t fit with the rest of XKit’s iconography, will make your extension seem amateurish and poorly developed.
Keep your icon simple. Focus your icon around a single symbol directly related to what your extension does. Try not to use more than one symbol per icon.
Avoid ambiguity. Though your icon should be simple, make sure it’s not vague. An abstract icon makes it hard to understand what your extension does.
Avoid realism. Keep your icon as simple as possible by using a symbol rather than realistic images.
Keep your backgrounds clear. Other than your central symbol, there shouldn’t be much in the background to distract from it.
Mind your colors. Use light background colors and avoid dark ones. Contrast the colors between your symbol and the background so that it doesn’t blend in.