Prepares for 2027 and 2029, for example (6)
I believe the answer is:
primes
'prepares' is the definition.
(priming is a kind of preparing)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for primes that I've seen before include "Prepares something for action - perhaps a pump" , "best parts" .)