>>>  emacs -Q
>>>  C-x C-f src/xdisp.c RET
>>>  M->
>>>  C-u 37100 C-p
>>>
>>> This signals an error "Beginning of buffer".
>>
>> Nice.  That's a recipe you concocted knowing the implementation 
>> details, didn't you?  😉
>
> Of course ;-)
>

Then here's another recipe with long lines detection enabled:

emacs -Q
C-x C-f src/xdisp.c RET
C-n
C-x i .../dictionary.json RET
M->
C-u 37100 C-p

😉