The .flprjzip file
is an ordinary zip file with a few extra files to give Flare some information about what was zipped. Change the file extension to .zip, and open it as a zip file if you want to.
Note that Flare replaces spaces in filenames with %20, and probably adds some control information too, so if you want to open a Flare-zipped project in Flare, you will need to unzip it using Flare. If you unzip it using an ordinary zip utility, Flare won't be able to open it. So it is proprietary in the sense that you need Flare unzip in order to access Flare-zipped files using Flare.
The one thing I wish is that Flare left out the Analyzer and Output folders from the zipped project, since it builds these dynamically when it needs them in the new project.
Are you absolutely sure that Flare doesn't just add these folders dynamically after unzipping the project? True, when Flare unzips the project, it generates these folders, but I've never found them to contain any stuff that had come from my old project. They're certainly not included in the .flprjzip file.
An advantage of Flare zip is that it backs up only what Flare needs to recreate the project elsewhere, and since V10, you can now zip on a target level too, which is useful if you only need to send some of the targets in a project for translation.
But if what you want is a safe backup of your work exactly as you left it before you go home, you may find an ordinary zip is better, especially, if like me, you occasionally have other working files lying around in other folders in your Flare project. If they aren't below /Content or /Project, Flare won't include these.
Of course, the best way to backup is to use a source control system, but you may not be in a position to make that happen, I know.
