Of course, options are completely cost free.
The application icon is part of the identity of an application. As such, it is the *one and only* icon you cannot customize in calibre. Historically, you could customize it as well. I removed that ability in 2.66, deliberately, and it is not going to change.
And if you are really that bothered by an icon feel free to modify the calibre source code and run it with whatever logo you like. Instructions on how to do so are in the User Manual.
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