This is the 7133rd most frequent Russian word.
брестская
"Брестская" means "of Brest" or "related to Brest," referring to the city in Belarus.
The word "брестская" means "Brest (adjective form)", denoting that it relates to Brest, in this case, describing the fortress.
Брестская крепость сыграла важную роль в истории.
Brest Fortress played an important role in history.
The word "брестская" is used here to describe the exhibition as pertaining to or originating from Brest.
Мы посетили брестскую выставку на ярмарке.
We visited the Brest exhibition at the fair.
The word "брестская" in this context describes items (souvenirs) that are from or associated with Brest.