There are several areas around pretty printers and debugging in general we want to investigate:

1. unique pointers are broken in gcc 11.2 (currently deployed toolchain)
2. std::set and static members sometimes is not printable when debugging with v4 gdb from v3/v4 compiled binaries
3. Corefiles have bad source files from when using v4 gdb with v3/v4 compiled binaries
4. The hang analyzer needs to be verified to be working with v4 gdb with v3/v4 compiled binaries.
5. some gdb "hangs" on std::error_code/std::error_condition pretty printers:

I will write a detailed doc outlining my experiments and results.