𝕏 is a Unicode character known as "mathematical double-struck capital X." The new logo is also nearly identical to the lowercase "x" in the Monotype font "Special Alphabet 4." ...

Unicode is a massive, sprawling effort that pairs a number to every unique character in a language, every punctuation mark, every math symbol, and much more.

The set was introduced in Unicode 3.1 in 2001. When mathematical symbols are included in Unicode, they become far more accessible to the entire world.