The article states that the idea of women viking warriors was believed to be "mythological embellishments—a belief colored by modern expectations of gender roles." what does this mean?

The author means that our view of Vicking women today is mythological, invented and romanticized.

Explanation:

Today women vickings are portrayed as great guards, independent and treated by society as people with the same value as men. Although Vicking women had more rights (for example, divorce rights) than all other women in European countries, this view of female independence in Vicking society is a mythological thing designed to cater to today's female ideals. This is what the author of the article wants to say when he says that female Vicking warriors are "mythological embellishments — a belief colored by modern expectations of gender roles."

The Vickings men were warriors. The women were responsible for taking care of the house, cooking, sewing, storing food for the cold winter, the rich had several slaves to help them, the poor had to do everything on their own.

Moreover, they could not sign contracts, nor borrow money on their behalf, could not be part of secular clergy, politics, and could not serve as witnesses.