I have one for Spanish--but I also have my reasons for not knowing it: That most instances of saying the date don't take an article.
Why did I learn this so late? Because my Spanish teacher--a heritage speaker, not a native speaker--made us recite the wrong thing for four years, since every class he made us say the date: "Hoy es domingo, el 28 de marzo de 2021." That is wrong. It should be: "Hoy es domingo, 28 de marzo de 2021."
It also doesn't help that a lot of Spanish learning materials in English have it wrong as well. I'm talking very popular sources [Collins Dictionary, Easy Spanish Step-by-Step, Wikihow, a lot of websites, etc.]. A conspiracy.