Yugoslav passports from 40 years ago are widely regarded as being one of the most powerful passports ever, with visa-free travel to almost all Western states [0].
The special passports did exist however, and were issued to residents of what used to be the Free Territory of Trieste[0], both in Italy and Yugoslavia. They were established by the Udine Agreement of 1955 (although the border was still disputed and finally settled only in 1975 by the Treaty of Osimo[1]).
I can't find many sources about the special passports online. There is a mention here[2].
Their main advantage was the possibility of using secondary border crossings between Italy and Yugoslavia that had less traffic and shorter queues.
[0] https://en.wikipedia.org/wiki/Free_Territory_of_Trieste
[1] https://en.wikipedia.org/wiki/Treaty_of_Osimo
[2] https://www.cambridge.org/core/journals/urban-history/articl...
Could you elaborate a bit on the “recording and loading cassette” part?
I’m really wondering!
http://www.zxdesign.info/cassette.shtml
https://sinclair.wiki.zxnet.co.uk/wiki/Spectrum_tape_interfa...