How can one differentiate between HTML and PHP paths when using RewriteRule in PHP?

When using RewriteRule in PHP, one can differentiate between HTML and PHP paths by checking the file extension in the RewriteRule condition. This can be done by using the %{REQUEST_FILENAME} variable to capture the requested file path and then using a regular expression to match the file extension. If the file extension is .php, the request should be redirected to the PHP file, otherwise, it should be redirected to the HTML file.

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)\.php$ $1.php [L]
RewriteRule ^(.+)\.html$ $1.html [L]