A phrase used in a mocking sense on 4chan, often as a reply to people to discredit their opinions due to them being transgender.
Due the anonymity on the site, every post looks the same, meaning people can imitate each other at will. So someone who might want to make fun of another person would say this as a reply, imitating an edit or additional note by the original poster.
"I think that the Elden Ringgame is good."
"I'm trans btw, not sure if that matters." (<-- not the original poster)
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".