The money is for the massive Olmsted Dam Lock in Paducah, Ky., which is massively over-budget. The earmark would increase the appropriations for the dam from $775 million to nearly $2.9 billion.
It is worth noting that (while the over-runs should be investigated for breathtakingly poor management and dubious contracting practices by the Corps of Engineers) the dam itself is viewed as important to commerce along the Ohio river. There are also obviously good reasons to end the shutdown regardless any greasing of the skids by the White House with McConnell. However, the timing is being criticized as another example of how national emergencies are used by members to raid the treasury.