Blue: To represent the trans* flag and recognize that one can still identify as trans* if they choose to.
Green: To represent the genderqueer flag and recognize that one can identify as genderqueer if they choose to.
White: Because the middle line of the abrosexual and abroromantic flags are white and to unify all abros* together.
Purple: The blur of societal norms to remind (us/them) that it's okay to break them.
Black: To represent the nonbinary flag and recognize that one can identify as nonbinary if they choose to.
Edit: Purple also represents the genderfluid flag to show solidarity with (our/their) changing gender siblings and that (we) can often overlap and identify as both!Abrogender is defined as "a gender that changes so fast that it can not be pinned down and/or having so many tiny aspects that you feel like you are continuously discovering your gender."
Abrogender was coined on or before January 6, 2018 by tumblr user telescopephil. The flag was created by uncommongenders on January 16, 2018, based on a rough sketch by tumblr user abrogender, which was created on January 14, 2018.