Print all Gmail labels

inbox-labels.js

// Go to the Inbox
// Unfold label menus (only labels visible to you will be collected)
// Open a console

var elementsWithDataLabel = document.querySelectorAll('[data-label-name]');

var dataLabelValues = Array.from(elementsWithDataLabel).map(el => el.getAttribute('data-label-name'));

dataLabelValues.forEach(value => {
  console.log(value);
});

settings-labels.js

// Go to Settings -> Labels
// Open a console

let list = document.querySelectorAll(".alC");

let items = Array.from(list).map(elem => {
  console.log(elem.innerText);
})