Project Backups vs. Ignition Gateway Backup
There are two main backup types that can be made in Ignition: a Gateway backup and Project backup.
Gateway Backup
The Gateway backup (*.gwbk file) includes everything you find in the Ignition Gateway webpage. This means all of the projects, global resources, Ignition tags, database connections, OPC and Device connections, plus all the settings of the gateway. The only things that aren't included in this backup is information stored in other programs, IE: the data in a database, PLC programs, etc.
Note that restoring a Gateway backup is the easiest way to restore your system, but it will overwrite all of the existing settings including your projects. There is no merge option for a Gateway backup.
Project Backup
A Project backup (*.proj file) is much smaller than a Gateway backup and only includes data from the selected project. This means all its resources such as windows, transaction groups, templates, reports, project scripts, etc. Notably missing from the project backup are any Gateway scoped resources, even if they are presented in the Designer. IE: Ignition tags, stored raster images, global items like SFCs, alarm pipelines, global script functions etc. When a project backup is made, it is recommended to also backup your tags, images, and anything else you might be using. While the project may rely heavily on a specific database connection or tag provider, those are not included in the project backup.
When you upload/restore a project backup in the Gateway Webpage, it will be merged into your existing Gateway. If there is a naming collision, you have the option of renaming the project or overwriting the project. Project backups can also be created/restored in the Designer. This will even allow you to select which parts of the project backup you want to include and will merge them into the currently open project.