One constant in the Star Trek universe are mirror and parallel worlds encountered by the Enterprise, Voyager, and Deep Space Nine crews. In the event of Warship Yar, it was actually the USS Enterprise-C that caused a new timeline to emerge: when the starship traveled roughly 20 years into the future and encountered the USS Enterprise-D.
In this new Star Trek: The Next Generation timeline, Lt. Yar hadn’t been killed by the encounter at Vagra II. Instead she continued serving as tactical officer aboard the Enterprise-D. However, after encountering the Enterprise-C and its crew, Warship Yar decided to travel back into the past so she could help their unfinished battle with the Romulans as tactical officer.
Given her greater overall experience in Starfleet, Warship Yar has skills in both Security and Command. Warship Yar’s traits are the same as her original timeline counterpart (Human, Federation, and Starfleet) however given her expanded skills it would be easy to recommend Warship Yar for any Away Mission involving matters of both Security or tactical coordination resulting from strong Command.