How is 4H‐1,4‐oxazocine aromatic?
According to Huckel's rule Four Criteria for Aromaticity
The molecule needs to be (1) planar, (2) cyclic, (3) fully conjugated, and has (4) 4n+2 electrons.
Your molecule does not seem to be planar (b/c of N and O atoms) but assuming that it has a nearly planar conformation it satisfies all other criteria.
You only need to count one of Oxygen's lone pair and the only Nitrogen lone pair:
10=4*2+2
So it could be aromatic (if it is nearly planar)