What
Git subprocesses now run with GCM_INTERACTIVE set to "never", alongside the existing GIT_TERMINAL_PROMPT: "0" and GIT_ASKPASS, so a Windows Git Credential Manager dialog cannot block a git command indefinitely.
Evidence
GCM_INTERACTIVE: hHt.GCM_INTERACTIVE
Strings lifted out of the shipped bundle, so the claim above can be checked against them.