PyCharm supports customisable lookups of library functions and methods via hotkeys, which are set in the Settings -> Tools -> Python External Documentation and some entry examples are here.
And then a hotkey can be assigned in the Settings -> KeyMap -> (search) External Documentation.
This does work in code, but mostly not in the Evaluate Expression window during debug. Is there any way to achieve the same functionality in the Evaluate Expression window during debug sessions?
I'm not aware of any workarounds or plugins to fix this.
I created a ticket in PyCharm issue tracker for this problem.