Blender SVN

blender-svn is a Blender add-on to interact with the Subversion version control system from within Blender.

Installation

Find installation instructions here.

Make sure you have an SVN client installed, such that typing svn in the command line gives a result. Just Google "how to install SVN on Windows".

Open a .blend file that is in an SVN repository, and enter credentials.
Download updates, commit changes, resolve conflicts, all from within Blender.
You can also add repositories in the add-on preferences UI.
A list shows all files in the repository that are outdated, modified, newly added, replaced, conflicted, etc, with the relevant available operations next to them.
The file statuses automatically update every few seconds. If you do an SVN operation, the file statuses update immediately.
Searching for a file name will also show files that aren't modified.
You can right click on a file to open it. If it's a .blend file, it will open in the current Blender instance, without loading the UI.
Entered credentials get saved to disk, so they get preserved even if the add-on gets disabled.
SVN Log is saved to disk, so a full log is always available and searchable, and you can easily revert a file or the whole repo to an older version.
If you're working in an outdated file, Blender will show a constant, very aggressive warning, since this could result in wasted work.

SVN Checkout is not supported due to limitations with giving progress feedback in the UI for such a long process. Do your checkouts via the command line.
The speed at which your SVN server can answer requests will greatly affect your experience using the add-on, or any other SVN interface.