Vocal treatises of the 18th c. and recent research suggest that Mozart's concert arias should be embellished with restraint. Appropriate ornaments include turns, filling-in patterns, appoggiaturas, and short cadences at elongated fermatas. Two arias--Alcandro lo confesso...Non so d'onde viene, K.294, and Bella mia fiamma...Resta, o cara, K.528--are discussed in more detail.
"Concerning the Performance of Mozart's Concert Arias K. 294 and K. 528,"
Performance Practice Review:
2, Article 4.
Available at: https://scholarship.claremont.edu/ppr/vol2/iss2/4