A Configuration Snapshot is an entity containing information about Jira configuration. All data in the snapshot is instance-independent, which means that it can be easily transferred to another Jira instance. There are a couple of different kinds of snapshots:
A system configuration snapshot contains the whole configuration of a single Jira instance (projects, workflows, schemes, screens, etc...). This means that you can use this snapshot to transfer all Jira configuration settings from between Jira instances.
A project configuration snapshot contains the settings for a number of projects including all configuration objects used by these projects. This kind of snapshot is used to move only selected project configuration between Jira instances.
A project with issues snapshot contains the settings for a number of projects including all configuration objects used by these projects as well as all the issues contained in these projects, including the comments, history data, Agile data, links, attachments, etc.. This kind of a snapshot is used to move the selected projects between Jira instances. This type of snapshot is available since CMJ version 5.0.