I originally advocated against all of 3.6 User and group database access, user-info and group-info, but there are solid arguments for them including the above observation by Lassi.
As long as we get back uids and gids from file-info, we need to be able to map them into human-readable name.
Therefore I advocate we remove group-info:members from the group-info record, and make a note about user-supplementary-gids in the 3.6 section.
Neutral on this one.
I further advocate along with Lassi that pw_gecos from the passwd struct be added to the SRFI in the user-info record. We could call it either full-name or full-name-field, the latter suggestion because other stuff has been added to it in times past.
We should consider if pw_shell in this struct satisfies the 80/20 rule, or omitting it violates people's expectations. Fields in a record from a struct are normally particularly cheap in pretty much every way.
Yes, keep it.
current-timezone, which can be picked up from the TZ environment variable, and in general deserves being part of its own SRFI.
The trouble comes when TZ isn't set, in which case you have to look at /etc/timezone, the system default timezone. The trouble here is that it's sometimes a plain file containing the timezone name, and sometimes it's a symlink to a particular file in /usr/share/zoneinfo. But since we have flushed the ability to read symlinks ...
Maybe it's better to bring back readlink after all.