Happy to find what's inside! (7)
I believe the answer is:
content
I believe this is a double definition.
'happy' is the first definition.
(associated in meaning)
'what's inside' is the second definition.
(the contents of something)
'to find' acts as a link.
(Other definitions for content that I've seen before include "Satisfied - subject matter" , "state of peaceful happiness" , "Gratify" , "Quietly happy" , "what's included" .)