Contradictory / confusing info on MCU clock speed

[black-puppydog]

In chapter 9, clocks and timers, there is this line: https://github.com/rust-embedded/discovery/blame/master/src/09-clocks-and-timers/for-loop-delays.md#L21

The processor inside the microcontroller is clocked at 72 MHz

but also this one: https://github.com/rust-embedded/discovery/blame/master/src/09-clocks-and-timers/one-shot-timer.md#L43

both APB1 and the processor are clocked at 8 MHz.

so, not sure which one it is, or if this is the same clock being talked about.