7 uses of UPDATE_UNKNOWN

theme_update_report in drupal/core/modules/update/update.report.inc
Returns HTML for the project status report.
update_calculate_project_data in drupal/core/modules/update/update.compare.inc
Calculates the current update status of all projects on the site.
update_calculate_project_update_status in drupal/core/modules/update/update.compare.inc
Calculates the current update status of a specific project.
update_manager_update_form in drupal/core/modules/update/update.manager.inc
Form constructor for the update form of the Update Manager module.
update_requirements in drupal/core/modules/update/update.install
Implements hook_requirements().
_update_message_text in drupal/core/modules/update/update.module
Returns the appropriate message text when site is out of date or not secure.
_update_requirement_check in drupal/core/modules/update/update.install
Fills in the requirements array.