For troubleshooting I needed to open the Nextcloud desktop client’s log. They are compressed in gzip format and I used 7-zip to open the archive. This gave me a moment of nostalgia when I noticed the Host OS column:
TOPS 20! That was the OS on the companies DECSYSTEM-20 time-sharing system when my career started around 1980.
According to the GZ spec TOPS-20 is associated with a value 10 for Operating System. On Windows this should be 11 for NTFS. But let’s not fix this tiny harmless bug and keep the memory of TOPS-20 alive.