Fannie Mae and Freddie Mac released a draft proposal this week on how they plan to boost underserved manufactured housing, rural housing and affordable housing preservation markets for low and moderate-income families over the next three years. Based on a federal law, the Federal Housing Finance Agency’s duty-to-serve rule requires the government-sponsored enterprises to increase financing in those three areas. The plans released this week are part of an extended implementation process. A large part of the duty-to-serve conversation has focused...