system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Vatican Secret Archives

Why does it exist ?? Are the protecting something?? Are they hiding something ?? What could that possibly be ?
gpt
It's an umbrella term for "Vatican important stuff that's not open to the general public."

Lots of people have access to different parts of the secret archives, you just need a reason. The Vatican (or at least the last few popes) have been remarkably good about letting researchers have access to these documents, as much or more so than most secular governments. 

These archives contain everything from papal diaries to political correspondence, in fact there was a letter penned by one of Abraham Lincoln's assistants, signed by Lincoln himself, addressed to the then-pope, found in the archives recently (for example). 

The secret archives are, for the papacy, like the attic is for your aunt, sure, there's probably some cool stuff in there (maybe a hidden gem here or there), but for the most part it's your cousins science projects and English homework from 1st grade on.