Not sure if that's a key, or a playground slide for your finger. What's "PTR CR/LF"? Maybe "printer", not "pointer". That would mean that there already are dedicated keys for all common line endings already ....
From the location of the backspace key, they evidently intended to penalise people who made mistakes :)
Nice Keyboard, those were the days they were built to last several (human) lifetimes. Having a industrial maintenance mechanic backround I know how reliable Micro Switch products can be, also when made in the U.S.A.