GCompris is a Mac application for use in reading email. It uses the free Text To Email service to send email. The application can be downloaded from the website (which also allows free trial downloads) or from the Mac App Store. It can only send email messages using the Text To Email service and not actually send them through any of the mail servers used by Apple. GCompris uses the address of the sending person and the recipient as part of the address when it is reading the message. It cannot read the message itself and therefore cannot send it. It is therefore safe to say that if you do want to get the use of this application, you will have to pay for it.
The Mac application that is available to download is called iMatter. The application was created by an independent developer named Justin Clarke. The free version of the application is available on the Mac App Store. However, the Mac application is a stand alone application and therefore does not run alongside the default Mac Mail application. You will not find this application listed in the applications or ports lists in the OS X Install Assistant. Therefore, there is no way to install the application using that tool.
The free version of the application requires an Internet connection to function. Therefore, it is essential that you are connected to the Internet when you install the application. This is because if you disconnect from the Internet, the free version of the application will stop working. In addition, it is necessary to download the GCompris application to your computer before you install it. It is possible to make an automatic download of the application using the website, but doing so will cause your computer to become unbootable as it will try to use the space available on your hard drive for the download.