A bugfix made in src/third_party/immer/dist/tools/gdb_pretty_printers/autoload.py was made locally in 10gen/mongo without merging into mongodb-forks/immer. [This PR](https://github.com/mongodb-forks/immer/pull/2) in mongodb-forks/immer was never merged, but the changes were made in 10gen/mongo in [6c931f25](https://github.com/10gen/mongo/commit/6c931f2516bbcb9f7fc6f9cd10bc1b1894f585af).

I think the change should be merged into mongodb-forks/immer and then src/third_party/immer/scripts/import.sh in 10gen/mongo should be updated to refer to the resulting git ref.