@thomasfuchs
However, that trademark is specified as
"The mark consists of a stylized letter "X". The left side of the "X" is white and the right side of the "X" is blue"
and
"The color(s) white and blue is/are claimed as a feature of the mark."
On the other hand, Elongated Muskrat just picked the standard Unicode letter 1D54F, described as "Mathematical double-struck capital X"
It'll be hard to argue that those are the same.