You can create a project snapshot any time by going to project settings following Snapshots tab. Even more, the project snapshots are created automatically once you import new strings or perform a search/replace, so you can always revert back to previous version (enable Automatic snapshot in upload).
Users at Business Growth and higher plans can enable Automatic daily snapshots option to keep backups accurate.
Restoring from a snapshot is done by creating a project copy from snapshot. All the project settings, contributors, comments, screenshots and statistics are preserved when restoring project copy from the snapshot.