Hi Kevin,
As Indicated on page About System Workbench for STM32 the source code for the version of OpenOCD we ship with System Workbench for STM32 has to be a patched version, as the standard version do not support all recent STM32 chips; this source code can be accessed by cloning our source base from the GIT server listed on this page.
ST people push their changes to the official development base but, as you know, getting them through takes some time so, as we want to provide support for th enew chips as soon as they are available, we need to integrate these patches ourselves and provide a custom OpenOCD version.
Bernard (Ac6)