The Yandex.Metrics Reports API is aimed to add extensibility to the Yandex.Metrics Reports module, which is a part of the Yandex.Metrics project.
Currently only one hook is available - hook_yandex_metrics_reports_list().
How to Use
Just implement the hook_yandex_metrics_reports_list() hook in your module to add a custom report/chart on the reports page.
Don't forget to clear the cache after adding new reports.