The earth pony who is pushing the unnamed zebracorn from the door is her nanny. This is going to be a side story of my bigger story/comic called Broken Ranks with the unnamed foal as the main character.
Her father, a succesful unicorn lord was embarrased about his daughter being part zebra, and she was born outside of wedlock… She suddenly showed up outside his door when just a couple of days old, so he has been hiding her this whole time, with her only friend being her nanny, who also is unnamed for your information.