Many times I've seen customers' management servers and gateways littered with remnants of the old exports or diagnostics archives.
Not to add to the mess, I like to use /var/CPbackup/backups/ as a repository for .tgz(s)
i.e.:
[Expert@CPMGMT:0]# ./migrate export /var/CPbackup/backups/CPMGMT_EXPORT_021620212037
You are required to close all clients to Security Management Server
or execute 'cpstop' before the Export operation begins.
Do you want to continue? (y/n) [n]? y
Copying required files...
Compressing files...
The operation completed successfully.
Location of archive with exported database: /var/CPbackup/backups/CPMGMT_EXPORT_021620212037.tgz
[Expert@CPMGMT:0]#
You can use Web UI as a side channel for download and upload capabilities, so long as you rename the needed file by appending .tgz, you have no difficulty "importing" it via Backup menus:
Using Backup for file transfers