This can be done using our REST API. You can use curl or other tools to send a GET request to /rest/library/data. This will return the information you are looking for and more. Please visit our documentation portal for more information: https://paxata.atlassian.net/wiki/spaces/PaxDocs/overview
It sounds like you're trying to download metadata about the datasets that exist in the Data Library. Our export features are built to facilitate export of the actual data to a variety of formats and destinations. There is no UI feature that allows you to do that.
However, the Paxata REST API does support these type of metadata exports.
Create a REST API Token:
Execute a GET request against the "/library/data" REST endpoint
Use a Terminal / Command Prompt / Shell: