• have GHINB extension installed
• open an empty vscode window
• open .vscode/notebooks/my-work.github-issues
• scroll to the end and back up
• take a heap snapshot
• scroll to end and back up, repeat 5 time
• take another heap snapshot and see a memory increase
• repeat the scroll 10 more times
• take another heap snapshot and even more memory is used

I chose GHINB because it has no outputs, meaning the leakage must be with the list, editors, editor contributions, or models. This reproduces with ease and also out of dev, so I am not uploading those snapshots here.