Each family subdirectory contains the `.ttf` font files served by Google Fonts, plus a `METADATA.pb` file with metadata for the family (such as information on the project designer(s), genre category, and license - [learn more](https://github.com/googlefonts/gf-docs/tree/master/METADATA)) and a `DESCRIPTION.en_us.html` with a description of the family in US English.
The `/catalog` subdirectory contains additional metadata, such as profile texts and portrait/avatar images of font designers, and this is open for contributions and corrections from anyone via Github.
The `/axisregistry` subdirectory contains metadata for the GF Axis Registry, containing information on variable font axes that can be found in the collection, including experimental axes.
If you find a problem with a font file or have a request for the future development of a font project, please [create a new issue in this project's issue tracker](https://github.com/google/fonts/issues).
Since all the fonts available here are licensed with permission to redistribute, subject to the license terms, you can self-host using a variety of third-party projects.
One popular service is [Fontsource](https://github.com/fontsource/fontsource), which offers bundled NPM packages.
For Linux, macOS, FreeBSD, or HaikuOS you can also use [fnt](https://github.com/alexmyczko/fnt), to install single fonts. For [RPM](http://bootes.ethz.ch/fonts/rpm/), [DEB](http://bootes.ethz.ch/fonts/deb/) based systems, feel free to try the linked URLs for individual fonts. Others can also use the [webservice](http://bootes.ethz.ch/fonts/).
You can also sync the collection with git so that you can update by only fetching what has changed. To learn how to use git, Github provides [illustrated guides](https://guides.github.com) and a [youtube channel](https://www.youtube.com/user/GitHubGuides), and an [interactive learning lab](https://lab.github.com).
Free, open-source git applications are available for [Windows](https://git-scm.com/download/gui/windows) and [Mac OS X](https://git-scm.com/download/gui/mac).
The SIL Open Font License has an option for copyright holders to include a Reserved Font Name requirement, and this option is used with some of the fonts.
These fonts are usually the result of collaborative projects, where you are invited to discuss issues with the designers and even contribute to their ongoing development.