Content purging is a feature that automatically deletes old versions of content (deemed useless and obsolete).
Content purging is not compulsory, but is highly recommended to reduce the size of the data stored by your application and thus boost performance (especially if your application handles a large volume of data).
This is an automatic process, which can be set up and configured by the application administrator.
The administrator defines the purge time, the number of days after which a content version is deemed too old, and the number of last validated versions that will not be deleted during the purge.
So, depending on the interval set by your administrator, the purging process is carried out regularly, and old versions of your content may be deleted. Restoring these versions will then no longer be possible.