Ways to observe clock signal of an STM32 MCU
Directly from the reference manual, pay attention to the last line.


Without oscilloscope you can use TIM5 to perform a comparison between two clocks.
Since TIM5 can input capture from LSI or LSE, you can compare the SYSCLK (the one TIM5 is running on) with any of those. TIM11 can do HSE.
Which is described in detail in chapter: 6.2.11 Internal/external clock measurement using TIM5/TIM11

I'd recommend to do this before using a crystal to check whether it is the expected freqeuncy.