Absgender is a gender modality that refers to when one is between, beyond or removed from cisgender/transgender dichotomy, and alternatively meaning a gender that is neither cisgender nor transgender.
If one sometimes experiences another gender(s), they could identify as absgender and transgender, or cisgender and absgender, or other combinations of gender modalities (as long as they fit the other term too), if they prefer it.
“Abs-” can be used as a prefix in the same way that “cis-” or “trans-” can be used as prefixes to describe one's gender in relation to their assignment.
The flag was created by the same user on the same date. Neither pink nor blue were used to represent removal from the concept of cisgenderness. White was also disclosed, as those colors together represent the transgender community. To reinforce the fact that non-binary identities are valid transgender identities, the colors yellow, purple and black were also avoided.
The name comes from the Latin word “abs-”, a prefix meaning “away (from)”, in this case referring to being conceptually ‘away’ from both explicit cisgenderness and transgenderness.