Why does it say "Generated in X seconds" in my PDF?

When the WP_DEBUG constant is set to true Gravity PDF will show debug information at the bottom of the PDFs it generates (PDF stats). If the constant WP_DEBUG_DISPLAY is also set, it will need to be true as well to display the debug information. This may look like:

Generated in 1.13 seconds
Compiled in 1.16 seconds (total)
Peak Memory usage 64.00 MB
Number of fonts 3

This is useful information when building a custom PDF template but not something you'll want enabled during production. You can disable this by setting WP_DEBUG to false in your wp-config.php file.