Tlalpan is a huge district of Mexico City, but Wikivoyage says:
The Centro Historico of Tlalpan comprises an area of maybe 6 x 6 blocks, which can be done by foot.
You can stroll through the streets around the Plaza de la Constitucion
Despite trying all kinds of searches in Google Maps, I am unable to find that place.
What are the latitude/longitude of the Plaza de la Constitucion, in Centro Historico of Tlalpan?

The Centro Historico of Tlalpan also has a large Spanish Wikipedia article, unfortunately without latitude/longitude information.