The following information is a direct copy of the official "Instructions Booklet" that you can find here (in English, French, German and Spanish language):
The Yashica FR I is highly precision 35 mm SLR camera incorporating the most sophisticated electronic systems that photo technology has to offer, It features a fully automatic aperture-preferred metering system with a silicon-photo-diode circuit for instantaneous exposure readouts when operated on AUTO. It also features manual override for those special situations when manual controls are handy, In addition, it maintains all of the advanced electronic features and systems advantages of the other cameras in the FR Series, including the Contax/Yashica mount for accepting a wide range of Yashica and Zeiss T* lenses.
The FR l's feather-touch electromagnetic shutter release makes possible blur-free pictures, and at the same time permits use of various remote control accessories such as cable switches and the Infrared Controller Set for wireless remote release. In addition, the electromagnetic release system also permits shutter release via the built in release button on the highly advanced RTF 540 electronic flash unit. And when the RTF 540 is used in conjunction with the Yashica Winder, the FR I is capable of sequential flash up to 2 frames per second.
Be sure to look into the countless other advantages of the FR I such as an interchangeable camera back to permit use with the Yashica Data Back, and hook-up with a variety of Contax and Yashica close-up equipment and other accessories.
More info from the "SLR Directory 1978" article (Modern Photography Magazine):
You can find scans from the complete article here: https://www.flickr.com/photos/nesster/4437577837
The viewfinder in detail:
And here some ADs: