Part, we're told, publicised in unveiling of a product, say (7)
I believe the answer is:
rollout
'unveiling of a product say' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'part we're told publicised' is the wordplay.
'part' becomes 'role' (eg a theatrical role).
'we're told' shows a homophone (sound like).
'publicised' becomes 'out' (I can't explain this - if you can you should give a lot more credence to this answer).
'role' is a homophone of 'roll'.
'roll'+'out'='ROLLOUT'
'in' acts as a link.
Can you help me to learn more?
(Another definition for rollout that I've seen is " Launch".)