matplotlibrc is multiple different configuration files; it's a hierarchy of configuration files that allows you to configure Matplotlib to behave differently for different users or different projects depending on what you need. By default, the hierarchy of which matplotlibrc config file overrides others begins with the one in the current directory, which oftentimes does not exist but ultimately will be the one that overrides all others.
The next one is within the matplotlibrc environment variable in that directory.
The third is within the config home, if you're running a Linux or BSD-based operating system with a directory called Matplotlib and a file called matplotlibrc.
Finally, with the Matplotlib installation ...
