Justice Democrats endorsement of Kerri Harris is a big deal
Founded in 2017 by Cenk Uygur of 'The Young Turks', and former leadership from the 2016 Bernie Sanders presidential campaign, Justice Democrats has a stated goal of reforming the Democratic Party by running "a unified campaign to replace every corporate-backed member of Congress and rebuild the Democratic Party from scratch."
You can't get anymore corporate-backed than Carper.