Heartgender is a xenogender related to lovecore, valentines, and love in general.
Similar terms include lovecoric and lovergender.
History
The term was coined by Twitter user britebuck on March 23, 2021, along with the flags.[1] It's possible that it had previously been coined by someone else, because its usage dates back before June 5, 2020. There is also a flag that predates the term's known coining.[2]