This extension is useful when your site has a Mosaico extension installed and you have either migrated your site to a new domain name (or synced your production database to a development or staging environment) or the extension directory path is changed.
CiviCRM civicrm_mailing and civicrm_mosaico_template tables hold the old domain name and extension directory path.
If you migrated to a new domain name without changing the domain name and path in the above 2 tables, then the mosaico template won't load due to an AJAX request on the old domain (a cross-domain request).
To avoid such issues, you can replace the domain and path as per your requirements.
Supporting organizations