[Localization] rescan from files

[K. K. Subramaniam]

Hi,

What exactly does Files-> Rescan from files do?
  1 add new files from project svn/git repo?
  2 merge changes checked into the repo through other programs.
  3 refresh contents from files in svn/git repo?

Is it same as the "update stores" op described in
  http://translate.sourceforge.net/wiki/pootle/commands

In case of 2) how can I check the diffs resulting from the merge to ensure that 
it has gone right?

For massive edits (e.g. find and replace), I have to fall back to doing direct 
checkins to Etoys svn. I would like to make sure that those changes can be 
merged back into Pootle. Is it sufficient to do just do a rescan?

Thanks .. Subbu