The most common and most likely answer to this crossword clue is the 10 letter word MANIFESTED
I've seen this crossword clue in The Guardian
M
A
N
I
F
E
S
T
E
D
Buddy explains!

The straight part
We know that "revealed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case revealed = manifested.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MANIFESTED mean?
MANIFESTED verb- To show plainly; to make to appear distinctly, usually to the mind; to put beyond question or doubt; to display; to exhibit.
- To exhibit the manifests or prepared invoices of; to declare at the customhouse.