They are targeting mixed imcome housing, with a focus on lower income and caregiver roles (teachers/emts/etc). The plus side is that the city will own these outright, unlike what it normally does which is fund non profits or lease land to for profits developers with a guarantee of a percentage of the units are low income, generally for a decade or so. Of course, the leases run well past that decade, so the business cleans up long term and low income people get forced out. This of course is always a sweet heart deal for the developers, as they donate large sums to the major and city council. This was a direct ballot initiative, and it won out over the poison pill alternative the council, mayor and the chamber of commerce also forced on the ballot.
The plans ive seen are for multi-unit structures, tending towards green building and social configs, i.e energy efficent building with inner courtyards and amenities. Everything ia still in the planning phase, though, so no actual number of units, but at that funding, with city owned land, I would expect 1000-2000 units/yr. Seattle is growing at a pace of roughly 12,000-15,000/yr, so this should address 10-15% of that growth with affordable, excellent housing.
Honestly, it most likely will not. The shit heads that this targets are perfectly fine setting up an office elsewhere and claiming they work there over 50% of the time.