Saber Alter in her costume from her final ascension artwork in Fate/Grand Order. It is a modified version of her third ascension outfit, now having Elbow Gloves instead of her Shrug (Clothing) and her skirt becoming shorter. She can also be seen wearing black Thigh Boots.
It's common for artists to mix-and-match elements of this ascension with her third ascension. If elements from both are visible, tag both ascensions.