According to the sources, referred in Wikipedia article about Umberto Eco, a writer and philosopher, explained the origin of his family name as follows:
Towards the end of his life, Eco came to believe that his family name was an acronym of ex caelis oblatus (from Latin: a gift from the heavens). As was the custom at the time, the name had been given to his grandfather (a foundling) by an official in city hall. In a 2011 interview, Eco explained that a friend happened to come across the acronym on a list of Jesuit acronyms in the Vatican Library, informing him of the likely origin of the name.
I'm failing, however, to find confirmation to this anywhere beyond Eco's self-evidence. What was the exact list of the acronyms? How many other Ecos are in Italy, did this last name indeed prevails among foundlings? Why the foundling hadn't actually get the last name of the family that adopted him?
In other words, quite frankly, I find this story quite suspicious, I failed to find any evidence by myself so I'm requesting the help of this community.
So, to reiterate, here's my question: Do we have any documental evidence that a) This Eco last name was indeed used for orphans in general by Catholic church and b) This is exactly the Umberto Eco's case in particular