Tintamarre skeleton/theme

I am studying the Tintamarre skeleton and I have one question regarding partials/navigation.html.twig. The designer makes references to menu items using uppercase followed by the t filter: {{ “MENU_HOME”|t }}. I could not find any reference in Google , the grav or Twig documentations. Can someone tell me the following:

  1. Where is MENU_HOME declared or defined? This question also applies to the other menu items.
  2. What does the “t” filter do? Not referenced in Twig doc.

Thank you in advance.

The |t-filter is a Grav-filter for translating a string, and MENU_HOME refers to the translation in languages.yaml.

Thank you Olevik. Your answer was spot on