This is a plugin for WordPress. Its purpose is to pull all Google webfonts into the WooThemes Canvas plugin - or any other plugin that uses the WooThemes framework - through the Google Developer API. Also additional subsets (sets of international glyphs) can be selected for all loaded fonts.
Alternatively download the plugin from within your WordPress installation. The plugin page is:
http://wordpress.org/extend/plugins/google-fonts-for-woo-framework/
The "releases" directory holds released zip files for convenience. The latest release is also available as google-fonts-for-woo-framework-latest.zip
You will need a Google Developer API Key to get access to the list of fonts that Google supplies. The plugin has a settings page that allows you to enter the API key. The plugin will refresh its list of fonts only when entering the settings page. If no valid API key is set in the plugin, then it will fall back to a fonts.json file that is refreshed each time this plugin is released.
The Google Developer API Key can be obtained for free here:
https://cloud.google.com/console?redirected=true
Some simple steps for obtaining the key are shown here:
http://code.garyjones.co.uk/google-developer-api-key
Note that Gary Jones' website may be slightly out-of-date now that the Googe console has moved. The web is full of moving targets these days, and articles get old quickly. But check it out anyway.
The code is styled more to PSR-1/PSR-2 than to the standard WordPress format. It's just a personal preference, and that's the way it is.