Before the 2nd Supergirl or Matrix or Mae was finally replaced by a "New" and True version of Supergirl Matrix would end up bonded to an Earth Girl Called Linda Danvers..... (which was the name used by the Silver Aged Supergirl in the 1960's until her demise in the 1st Crisis )
But when she finally broke free of that bond, Matrix took on a younger look and a new costume.
This Costume was a nod to the Justice League of America cartoon series. In a costume that looked more home made, the Maid of Might continued to fight along side the other Heroes of the DC Universe until she was replaced by a new version of the original Kara Zor El. Where Matrix went I am unsure, but she was soon forgotten in the New "Reboot" DC universe of the 2000's
Here is my take on the White Homemade Supergirl costume.
Next Time she is really back !
Until then ENJOY !