When RapidWeaver publishes your website, an optional backup of the RapidWeaver project file can be uploaded at the same time. The project file is compressed as a ZIP file, and is placed in a secret folder on your website, meaning that if you know the address it can be downloaded and re-used. You can enable backups to happen every time you publish, or on a less regular schedule. Backups only occur when your site is published, and do not happen in the background.
Note: RapidWeaver does not store your publishing password in project files. Your server address and username are stored in the document, with the password securely stored in the OS X Keychain. When saving your projects, RapidWeaver receives a reference to the keychain item from OS X, which it then stores in your document. In short: your password stays private, and you don’t need to re-enter your password on any Mac that has your publishing password in the Keychain.
Project backup will increase the amount of time taken to publish your website. RapidWeaver cannot use multiple concurrent connections to upload a backup, as concurrent connections can only be used to upload different files.