Please, Can You Help Me Understand IDA's New Private Sector Window?

The World Bank’s soft lending arm for poorer countries, IDA, is busy rolling out a new $2.5 billion Private Sector Window. (See last year’s outline proposal for reference.) Bigger private sectors in IDA countries would be hugely welcome, so there is much to like in the broad thrust of the proposal, as suggested by Nancy Lee. But I’m left a little baffled by the details, and would love some reactions as to what I’m missing.