D-modules on algebraic stacks

For Lectures 4.3 and 5.4 we'll need a more down-to-earth understanding of D-modules on algebraic stacks.

This has an excellent exposition in Section 1 of [BD]. (Here and in other places, [BD] refers to "Quantization of Hitchin's integrable system and Hecke Eigensheaves" by Beilinson and Drinfeld.)