"ST" often refers to STMicroelectronics (like STM32 microcontrollers), but they don't typically offer a tool by that exact name.
It is possible that the name is a combination of two different things or contains a slight typo. To provide you with the review you're looking for, could you clarify a few details? ST-9zip
This is the most common open-source file archiver. knowing the context would help.
If this is for a specific industry or a specialized coding environment, knowing the context would help. ST-9zip