We have moved the project space for this extension to CiviCRM's Gitlab. This includes both the issue tracking and support, and merge requests.
The new URL is: https://lab.civicrm.org/extensions/activitytypeacl
All issues have been migrated to: https://lab.civicrm.org/extensions/activitytypeacl/-/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