"STM32 Cores" by STM Installed OK but Not in Boards List


I have installed the STM32 Cores package by STM which downloaded from Github and installed OK. It is shown as installed in the Board Manager listing. But the whole package is missing from the Tools>Board: drop down selection list.

Is there something I need to do to have Blue Pill appear on the list?

Thanks in advance!


We need you to provide a detailed description of how you installed the STM32 Cores package.