In my opinion the icons for the menubar (sorter) and Safari extensions can be made clearer, easier to see. The menubar icon is kind of a black blob and it’s difficult to differentiate it from other black blobs, and the Safari icon is not only different but also contains many details which makes it difficult to find. I would like to see two simpler, clearer icons instead.
I second that.
And if you asked me how the icon should look like I’d point you right at the icon in the upper left corner of this very page. This, in black and white of course and with distinct lines.
You could use it in the PopClip extension too and provide it to others like Apple for its Shortcuts app, to Drafts for their actions, and to Reeder which at the moment uses a blurry greyscale scan of the app icon. To name just a few apps that have actions or extensions with associated icons.
And if you asked me if I liked this stripped down to the basics icon so much that I preferred it over the app icon of DEVONthink 3 and hoped that it would replace it I’d reply: Yes, I do.