I created an achromatic icon for my add-on, but it may be a challenge to stay visible due to the different theme colors people have in their browsers.
I've noticed that many of the native browser icons adjust themselves based on whether the theme is dark or light, so I designed both an all-black and all-white version of my icon. However, after researching, I couldn't find an easy way to switch between the two based on the user's theme in the add-on manifest. Why is this functionality available natively, but not for add-ons?