What does the cryptic crossword clue "A niche car's remodelled? That's being sentimental (10)" mean?

The wordplay uses an anagram. anagram of A + NICHE + CAR'S = SACCHARINE The answer is SACCHARINE.

A niche car's remodelled? That's being sentimental (10)

Daily Mail Cryptic #17232 | 13 Down | 2023-11-20 flower