ESSER is the Elementary and Secondary Schools Emergency Relief funding, as this round we're in now is ESSER III, the largest yet.
The frequently asked questions sheet clarifies the rules for states to review local plans for spending the money from the American Rescue Plan and other relief aid that will flow to school districts. It makes clear that state legislatures or departments of education cannot limit how localities use the money, as long as the uses are within the bounds of the federal law. And states and localities cannot use the relief aid to replenish "rainy day" funds.
And interesting point:
School construction is an allowable use for Covid relief funds--including new projects, renovations to ventilation systems, and purchasing trailers. But the guidance cautions against large capital projects that will require too much money and entail not only approval from the state but complex requirements for using federal money for such purposes.
This piece in the THE Journal spells out the allowable uses rather well.
You might also find this interview with the Acting Secretary of Elementary and Secondary Education Iam Rosenblum of interest.
The following bar graph was shared at Tuesday's Board of Ed meeting, showing Massachusetts (state total) amounts and timelines for when the funding expires: