I often find free download resources for font faces. I usually download the file and then double click ,expand, install with Font Book. It has never been clear to me if Font Book copies the font files to a system folder or if I need to keep the original file. I have encountered some fonts that became corrupt at a later date and I wasn't sure if that was because the original file couldn't be found. Can anyone verify that it is safe to trash the downloaded file after installation?