Why does the ‘git blame’ timeline sometimes appear in vscode, and how do I hide it?

I also unintentionally opened blame history and didn’t know how.

The reason why the timeline is opening unexpectedly is that clicking the message above the first line in a file opens and close the latest blame – see red area in the screenshot.

To fix it (thanks GitKraken for the advice on Twitter):

Command/ctrl + shift + P > GitLens: Open Settings > then scroll down to Git CodeLens: