Catalog file location for new Lightroom 7.2?

Lightroom creates a Library file, not a catalog file. It is called 'Lightroom Library.lrlibrary' and is hard-wired to be stored in your Pictures folder. You can't move it to another location. It is not really a catalog (like Rob said, the catalog is in the cloud) but a cache to speed things up by keeping certain stuff locally.

"is a catalog file for LR 7.2?" Well there is kinda, but you won' t see if because its master copy exists in the Lightroom Cloud.

"Is there a way to move a full edited catalog to LRC!" Simply, No. But you can set up Lightroom-Classic to sync so that all photos in Lr download to the LrC Catalog.   SYNC SETUP IN CLASSIC 

The sync can download the photos to a Dated Folder structure, and TBMK any Albums in Lr will create equivalent Collections in the LrC catalog.