This vector shows which characters are not encoded in the credentials part of the URL.
const anchor = document.createElement('a');anchor.href='//example.com';
anchor.username = String.fromCodePoint($[i]);
if(!/%/.test(anchor+''))log($[i])anchor.href='//example.com';
anchor.username = String.fromCodePoint(33);
if(!/%/.test(anchor+''))alert(33)anchor.href='//example.com';
anchor.username = String.fromCodePoint(36);
if(!/%/.test(anchor+''))alert(36)anchor.href='//example.com';
anchor.username = String.fromCodePoint(38);
if(!/%/.test(anchor+''))alert(38)anchor.href='//example.com';
anchor.username = String.fromCodePoint(40);
if(!/%/.test(anchor+''))alert(40)anchor.href='//example.com';
anchor.username = String.fromCodePoint(41);
if(!/%/.test(anchor+''))alert(41)anchor.href='//example.com';
anchor.username = String.fromCodePoint(42);
if(!/%/.test(anchor+''))alert(42)anchor.href='//example.com';
anchor.username = String.fromCodePoint(43);
if(!/%/.test(anchor+''))alert(43)anchor.href='//example.com';
anchor.username = String.fromCodePoint(44);
if(!/%/.test(anchor+''))alert(44)anchor.href='//example.com';
anchor.username = String.fromCodePoint(45);
if(!/%/.test(anchor+''))alert(45)anchor.href='//example.com';
anchor.username = String.fromCodePoint(46);
if(!/%/.test(anchor+''))alert(46)anchor.href='//example.com';
anchor.username = String.fromCodePoint(48);
if(!/%/.test(anchor+''))alert(48)anchor.href='//example.com';
anchor.username = String.fromCodePoint(49);
if(!/%/.test(anchor+''))alert(49)anchor.href='//example.com';
anchor.username = String.fromCodePoint(50);
if(!/%/.test(anchor+''))alert(50)anchor.href='//example.com';
anchor.username = String.fromCodePoint(51);
if(!/%/.test(anchor+''))alert(51)anchor.href='//example.com';
anchor.username = String.fromCodePoint(52);
if(!/%/.test(anchor+''))alert(52)anchor.href='//example.com';
anchor.username = String.fromCodePoint(53);
if(!/%/.test(anchor+''))alert(53)anchor.href='//example.com';
anchor.username = String.fromCodePoint(54);
if(!/%/.test(anchor+''))alert(54)anchor.href='//example.com';
anchor.username = String.fromCodePoint(55);
if(!/%/.test(anchor+''))alert(55)anchor.href='//example.com';
anchor.username = String.fromCodePoint(56);
if(!/%/.test(anchor+''))alert(56)anchor.href='//example.com';
anchor.username = String.fromCodePoint(57);
if(!/%/.test(anchor+''))alert(57)