Constant lexical_util::format::CXX20_HEX_LITERAL

pub const CXX20_HEX_LITERAL: u128 = NumberFormatBuilder::new()
    .required_exponent_notation(true)
    .digit_separator(num::NonZeroU8::new(b'\''))
    .mantissa_radix(16)
    .exponent_base(num::NonZeroU8::new(2))
    .exponent_radix(num::NonZeroU8::new(10))
    .case_sensitive_special(true)
    .internal_digit_separator(true)
    .build(); // 13_302_989_070_119_887_530_444_933_656_219_764_748u128

Number format for a C++20 literal hexadecimal floating-point number.