chars-that-are-uppercase-variants.js

let aToZ = new Set('abcdefghijklmnopqrstuvwxyz'.split(''));
let aToZ_Match = /[a-z]/i;
for (let i = 0; i < 100000; i++) {
    let char = String.fromCharCode(i);
    
    if (aToZ.has(char)) continue;

    if (!aToZ.has(char.toLowerCase())) continue;

    if (aToZ_Match.test(char)) continue;

    console.log(i, char, char.toLowerCase())
}

// 8490 'K' 'k'
// 74026 'K' 'k' (duplicate)