Fira System Font Replacement
These fonts are intended as a system font replacement on Mac OS X 10.10 Yosemite.
They are based on the Fira Sans font family and are licensed under the Open Font License (OFL) 1.1 or later. This package has been prepared by Jens Kutilek https://github.com/jenskutilek/FiraSystemFontReplacement.
How to install:
Download and unzip the font files from http://www.kutilek.de/download/fira-system-fonts.zip.
Copy the 3 font files into the /Library/Fonts folder on your system disk.
You may have to log out and in again in order to see the change take effect.
How to uninstall:
Delete or move the font files from the /Library/Fonts folder.
Known bugs:
The baseline of the bold font is too low in the menu bar.
How does it work?
These Fira fonts have a special name table with names identical to those of the system fonts. Because the font folder /Library/Fonts takes precedence over the fonts which are in /System/Library/Fonts, these specially crafted fonts are used for the user interface instead of the real system fonts. The original system fonts are not deleted or modified in any way.