Another way of saying a similar theme already explained by others, is that just like pandoc itself, the logo design focus on the "structure" instead of a representation of it.

That means we can have an image like above, and at the same time have font versions of it, where all of them are different representations of the same "logo".

Then people can feel free to use the different "variants" of the logo, where all of them hopefully recognizable as the pandoc logo as they all shows the same "structure".

e.g. the icon comes with a package, or the image used at the top of the official website, can be from the "official" image file. Then the favicon can be another image, perhaps generated from a font taking into account favicon are often viewed in much smaller viewing angle (using smaller font size variants of the same font family if available?) Then in a document if someone type \pandoc then pandoc can dispatch what it "draws" depending on the output formats (it can be just 1 font based and fall back to image based for simple logic.)