|Syncro SVN Client Views / Properties View|
The svn:externals property can be set on a folder or a file. In the first case it stores the URL of a folder from other repository.
In the second case it stores the URL of a file from other repository. The external file will be added into the working copy as a versioned item. There are a few differences between directory and file externals:
The path to the file external must be in a working copy that is already checked out. While directory externals can place the external directory at any depth and it will create any intermediate directories, file externals must be placed into a working copy that is already checked out.
The external file URL must be in the same repository as the URL that the file external will be inserted into; inter-repository file externals are not supported.
While commits do not descend into a directory external, a commit in a directory containing a file external will commit any modifications to the file external.
The differences between a normal versioned file and a file external:
File externals cannot be moved or deleted; the svn:externals property must be modified instead; however, file externals can be copied.
A file external shows up as a X in the switched status column.
Incomplete support - In subversion 1.6 it is not possible to remove a file external from your working copy once you have added it, even if you delete the svn:externals property altogether. You have to checkout a fresh working copy to remove the file.