Comment by b0in
Someone in the mailing list thread linked the man pages that they were able to extract out
https://gitlab.com/segaloco/v1man/-/blob/master/man1/stat.1?...
for sdrwrw:
- column 1 is s or l meaning small or large
- column 2 is d, x, u, -; meaning directory, executable, setuid, or nothing.
- the rest are read-write bits for owner and non-owner.
Pretty interesting. I guess it was way later, when they came up with the SUID semantics and appropriated the first character for symlinks (l) or setuid binaries (s)...