File:Enderian (Endergender) 2 by comet-queer Jan-10-2021 .png

Source

[Image ID: A flag with 5 horizontal stripes. The top and bottom stripe is black, followed by a dark purple stripe, and divided by a broad light purple stripe. End ID.] (Image ID Source)

The date may not be exact, it is the date of the earliest findable reblog of the flag, the account the flag is from is now deactivated.