What does the cryptic crossword clue "Engineer grabs files showing reinforced material (10)" mean?

The definition is "material". The wordplay uses an anagram. anagram of GRABS + FILES = FIBREGLASS; definition: "material" The answer is FIBREGLASS.

Engineer grabs files showing reinforced material (10)

Daily Mail Cryptic #17057 | 25 Across | 2023-03-20 flower