...The fonts are based on version 4.106 of the Fira Sans font family by Erik Spiekermann and Ralph du Carrois, and are licensed under the Open Font License version 1.1 or later. This package has been prepared by Jens Kutilek. Download and unzip the installer file from the Releases section. Right-click Fira System Fonts.pkg and choose "Open" from the context menu. In the alert about the package coming from an unidentified developer, click "Open" again. Follow the instructions in the installer and restart your computer when the installation process has finished. It is recommended to shut down, turn off, and restart your computer to finish the installation of the fonts. ...