Renaming remote folder, sane check

[Pablo Olmos de Aguilera C.]

In an attempt to make my like simpler, I renamed every remote folder to
lowercase (in gmail), and I fixed the nametrans so it doesn't to re-create
folders than doesn't actually exists.

Before doing that dangerous operation, I ran it with the parameters[1]: -1 -o
--dry-run, resulting in a some sort of different output, so I'm not sure it's
actually doing what I want:

[...]
Folder fran [acc: gmail]:
 Syncing fran: Gmail -> Maildir
 [DRYRUN] Copy 4 messages from fran[gmail-remote] to gmail-local
 [DRYRUN] Deleting 2 messages (1150,1681) in Maildir[fran]
[...]

This is one of the renamed folders (original name was capitalized), as I said, I
don't remember seeing that `Maildir[fran]`, but maybe it's only because it's
deleting? Anyway... my guess is that is deleting in my local machine (which is
fine), but I'd have expected something similar as above: `fran[gmail-local]`.

[...]
Folder [Google Mail]/All Mail [acc: gmail]:
 Syncing [Google Mail]/All Mail: Gmail -> Maildir
 [DRYRUN] Copy 298 messages from [Google Mail]/All Mail[gmail-remote] to gmail-local
 [DRYRUN] Deleting 171 messages (55201, [...] ,158492:158499) in Maildir[all_mail]
 Adding flag S to 6 messages on all_mail
 Deleting flag F from 1 messages on all_mail
[...]

What are those flags S and F? I've looked the docs but I couldn't find any
reference about it's meaning. Are those from the 2.3.2 point here[2]? (S: seen,
F: flagged, ecc?).

If I did the above and I'm getting this output, can I be sure that I won't
destroy any data? Is that the 'expected' output?

[1] offlineimap is configured with readonly True, this time... I normally don't
use it though.
[2] http://james.apache.org/server/rfclist/imap4/rfc2060.txt