Hello,
We have moved the project space for Mosaico Extras extension to CiviCRM's Gitlab. This includes both the issue tracking and support, and merge requests.
The new URL is: https://civicrm.org/extensions/mosaico-extras
To report a issue you can use the following link: https://lab.civicrm.org/extensions/mosaicoextras/issues
If you do not already have an account on CiviCRM's Gitlab, you can create an account by registering on https://civicrm.org/user
Thank you!