copy selected layer names (sub layers), by Script ?

//@target illustrator
app.preferences.setBooleanPreference('ShowExternalJSXWarning', false); // Fix drag and drop a .jsx file

// Main function
function main() {
  if (!documents.length) return;
  if (!selection.length || selection.typename === 'TextRange') return;

  var doc = app.activeDocument;
  var sel = app.selection;
  var names = [];

  for (var i = 0; i < sel.length; i++) {
    var str = getName(sel[i]);
    if (!isEmpty(str)) names.push(getName(sel[i]));
  }

  if (names.length) setClipboard(names.join('\n'));
}

// Get item name of different types
function getName(item) {
  var str = '';
  if (item.typename === 'TextFrame' && isEmpty(item.name) && !isEmpty(item.contents)) {
    str = item.contents;
  } else if (item.typename === 'SymbolItem' && isEmpty(item.name)) {
    str = item.symbol.name;
  } else {
    str = item.name;
  }
  return str;
}

// Check empty string
function isEmpty(str) {
  return str.replace(/\s/g, '').length == 0;
}

// Copy dummy TextFrame content to clipboard
// Function by Tom Scharstein https://github.com/Inventsable
function setClipboard(str) {
  var prev = app.selection;
  selection = null;
  var idoc = app.activeDocument;
  var tlayer = idoc.layers.add();
  var tframe = tlayer.textFrames.add();
  tframe.contents = str.replace(/^\s*||\s*$/, "");
  tframe.translate(10);
  tframe.selected = true;
  app.copy();
  tlayer.remove();
  app.selection = prev;
}

// Run script
try {
  main();
} catch (e) {}