How to choose 32F105

[vitecd]

I can see 32F105 variants in the source code but it's not available to select from the Arduini IDE. What I'm doing wrong, please?

[fpistm]

Nothing. There is no STM32F105xx declared. If you want to add it feel free to provide a PR following this wiki:
https://github.com/stm32duino/Arduino_Core_STM32/wiki/Add-a-new-variant-%28board%29