I'm trying to access the file of a pre-installed font on OSX. Where is the location of core, pre-installed fonts on OSX? The Library folder only contains fonts you've installed.
The default install of Mac OS X includes fonts in both of the following folders:
While I believe the following Fonts folder exists, there are no fonts installed in it by default:
Alternatively, if you know the name of the font, you can select it in Font Book.app and choose Preview > Show Font Info. The location is listed like in the image below.
You can also right-click (Control-click) on the font in the "Font" column and choose "Reveal in Finder"
Apple provides a list of directories here: http://support.apple.com/kb/HT2435