Python

    python3 -c "some·identifier = 0; print(some·identifier)"

C

    echo -e '#include <stdio.h>\nint main() { int some·identifier = 0; printf("%d", some·identifier); return 0; }' | gcc -x c -o temp - && ./temp

C++

    echo '#include <iostream>\nint main() { int some·identifier = 0; std::cout << some·identifier; return 0; }' | g++ -x c++ -o temp - && ./temp

Ruby

    ruby -e 'some·identifier = 0; puts some·identifier'

Javascript

    node -e 'let some·identifier = 0; console.log(some·identifier);'

Rust

    echo 'fn main() { let some·identifier = 0; println!("{}", some·identifier); }' > temp.rs && rustc temp.rs && ./temp 

Go throw an invalid character U+00B7 '·' in identifier

Java throw error: illegal character: '\u00b7'

C# is really annoyed with it apparently:

    echo 'using System; class Program { static void Main() { int some·identifier = 0; Console.WriteLine(some·identifier); } }' > Program.cs && mcs Program.cs && mono Program.exe

Program.cs(1,60): error CS1056: Unexpected character `·' Program.cs(1,60): error CS1525: Unexpected symbol `identifier', expecting `,', `;', or `=' Program.cs(1,99): error CS1056: Unexpected character `·' Program.cs(1,99): error CS1525: Unexpected symbol `identifier'

That’s it for the top in TIOB index I tested in the frame of this message.