Transaction response modification within interconnect circuitry

Apparatus comprising:

• response modification means for:
• storing identification data for modification target transaction responses in a shortlist buffer;
• identifying, using the identification data stored in the shortlist buffer, a modification target transaction response in a stream of transaction responses in transit from a transaction slave to a transaction master;
• and
• modifying the modification target transaction response to form a modified transaction response to be sent to the transaction master.

A method comprising:

• storing identification data for modification target transaction responses;
• identifying, using the identification data stored in a shortlist buffer, a modification target transaction response in a stream of transaction responses in transit from a transaction slave to a transaction master;
• and
• modifying the modification target transaction response to form a modified transaction response to be sent to the transaction master.