A csar file extension is related to the Caris Spatial Archive file format. A csar file stores bathymetric data.
CSAR file extension - Caris Spatial Archive
What is csar file? How to open csar files?
File type specification:
The csar file extension is associated with the Caris Spatial Archive, a data storage file designed for storing large amounts of bathymetric data developed by CARIS.
The csar file was used by CARIS applications.
This csar file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.