The main purpose of this extension is to provide a way to manage your custom metadata records on Salesforce orgs as csv.
This extension gives you the possibility to export records of your custom metadata in a csv so that you can modify them as if they were data. It also gives you the possibility to import the modified csv, and it will create for you, in the customMetadata folder of your sfdx project, deployable files for your Salesforce org.
How to use it
It is advisable to first extract the custom metadata csv via the export function and work on the generated file. So that you can use the import function that will create the .md-meta.xml files in the CustomMetadata folder of your Salesforce project. Files that via the standard deployment functionality you can deploy to your environment.