“A new exhibit hosted by Museum of Templo Mayor in Mexico City marks the 45th anniversary of the discovery of a monolith depicting Coyolxauhqui, the Mexica lunar goddess. The finding was a milestone for Mexican archaeology, as it shed light on Mexica civilization before the Spanish conquest. ‘Coyolxauhqui: The star, the goddess, the discovery’ displays more than 150 archaeological objects focused on the mythology, symbolism and scientific research around this deity (whose name is pronounced Koy-ol-shauw-kee). The exhibit runs through June 4.” “When the country regained its independence, the heart of the capital was densely populated, which complicated any excavation plans. But then Coyolxauhqui appeared. In 1978, near Mexico City’s cathedral where many thought the ruins of Templo Mayor were buried, an electrical worker hit something with his shovel. It was Coyolxauhqui, carefully portrayed in stone as the dismembered lunar goddess who lost a battle against her brother, the Sun. The discovery was a turning point.”—”New exhibit explores significance of Mexica’s lunar goddess”
I’m not finding a specific page about this “Coyolxauhqui: The star, the goddess, the discovery” listed as and exhibit at Museum of Templo Mayor, but there’s a few pages with references to Coyolxauhqui, such as Nuestra sangre, nuestro color. La escultura polícroma de Tenochtitlan and Sala 4: Huitzilopochtli. So, there may be a special exhibit, but also the Coyolxāuhqui stone appears to be central to the museum’s history.