There is a YIMBY group in my city and I swear half the Twitter followers have "dev op" or "scrum pro" in their profile.
They also seem to have no interest in any other broader social or economic issue. Zip about poverty, climate change, reproductive rights, trans rights, etc. It's about market housing. Pure and simple.
Yes In My Backyard, opposed to the NIMBYs of the suburbs or older housing developments that, through voting and showing up to city council meetings, keep new apartments and higher-density housing from being built.
YIMBYs can still be very bad. They can be techbros, libertarians, or astroturfed real estate developers. Along with libs that are slightly better than NIMBY libs.