How does "__doc__ % globals()" work?

[Jaime]

Hi all. Line 102 of https://github.com/python/peps/blob/master/pep2html.py says:

print(__doc__ % globals(), file=out)

and I've just spent all day trying to understand "__doc__ %
globals()". Sure, I realise that globals() is a standard-library
built-in functions that returns a dictionary representing the current
global symbol table, and that the result of this expression is the
value of the dictionary where the key is "__doc__", but I can't
understand how this works.

I've searched through dictionary tutorials to see whether they mention
accessing dictionary values using a % (percent) operator, and they
don't.

I've searched through printf-string formatting tutorials, and they all
say that I need a %-sign to start, and then some parentheses, so it
can't be that either.

Can someone please put me out of my misery - what, exactly, is the
percent (%) sign doing in the expression "__doc__ % globals()"?

Thank you!