expression, noun-modifying (irregular)
world-class; of high global reputation
Fixed prenominal phrase used to describe something Japan or a Japanese entity can be proud of on a global scale. Often appears in promotional or formal contexts.
This is a technology that Japan can boast to the world.
We want to protect our world-class cultural heritage.
A fixed phrase composed of 世界 (world) + に (particle) + 誇る (to boast, be proud of). The exact origin as a set expression is uncertain, but it follows a common pattern for attributive phrases in Japanese.