This is the chassis from a SAGEM TX-20 teleprinter keyboard, made around 1985 based on the date code on the IC (8515). The switches were Cherry M7 Style D (UncleFan received the different types and I just have some of the regular switches).
The space bar position has four holes, but it is not clear why. UncleFan reports that no switches had four terminals; the photo from 10ko shows the switch removed but two holes still containing solder, indicating that only two holes were used.
These keycaps are not from Clare. They are the same brand as that found on most BBC Microcomputers, and use a less-common internal structure (only found elsewhere in a single BBC Micro keycap). The plastic is so brittle that the stems crack when placed back onto the switches! One of the keycaps arrived already broken; the rest have the stem wrapped in self-adhesive tape to hold them together.
Most of the photos are from 10ko and were taken in 2019 (the EXIF data is incorrect). The keycap close-up photo is mine.