The most common and most likely answer to this crossword clue is the 6 letter word UPROSE
U
P
R
O
S
E
Buddy explains!

The straight part
We know that "Developed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case developed = uprose.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 UPROSE mean?
UPROSE verb- To rise; to get up; to appear from below the horizon.
- To have an upward direction or inclination
- To rebel or revolt; to take part in an uprising.