Spoilers (kinda) ahead
So... if you've been keeping up with Rebels and remember my earlier hopes for Ahsoka's entry onto the show... looks like I may have gotten my wish. By now it's a pretty popular theory that Hera's mysterious informant is in fact Ahsoka, and the evidence is quite compelling. When pitched upward their voice sure sounds like Eckstein, that symbol is kinda like Ahsoka's forehead marking, and it just makes sense that Ahsoka would be a reclusive freedom fighter by this time. I said I had hoped she would appear incognito, friendly yet also threatening, and we'd have to wait a while for the reveal, ala Marble Hornets. And wow, if this Fulcrum person is Ahsoka, kudos to the writers on reading my mind/stealing my ideas again!
Anyway, here's adult Ahsoka in disguise with that symbol etched on her mask.