Not sure if I understand your question correctly.
Since Wordpress requires a PHP runtime which gh-pages does not provide, uploading .php files would only result in people seeing the source code when visiting the GitHub page.
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
Not sure if I understand your question correctly.
Since Wordpress requires a PHP runtime which gh-pages does not provide, uploading
.php
files would only result in people seeing the source code when visiting the GitHub page.