Help me understand "Deprecate legacy shell escaping and quoting runner shell executor"

I’m trying to understand the change in behavior but I’m struggling to find any examples of before and after. I have GitLab 16.8.4 and planning on upgrading to 17.3.1. So far, I know I can enable FF_USE_NEW_SHELL_ESCAPE in the current version to test the new behavior, but I don’t know exactly what to test or what is expected to break.

What exactly changes between the “legacy escaping method” and the “FF_USE_NEW_SHELL_ESCAPE method”?