Austin faces an “existential crisis” of low housing supply and rising costs, Mayor Steve Adler has said. City leaders are pushing forward with some relatively modest changes to the land development code that could boost that supply, such as making it easier to build detached accessory dwelling units — backyard dwellings sometimes called granny flats. In this story, ABJ gets reactions about those changes from the companies building the kind of infill and missing-middle housing the city needs.