This local source record summarizes "National Observatory report on the Kumburgaz video cassette", published or preserved by TUBITAK report / independently hosted reproduction.
The page reproduces a report attributed to TUBITAK's National Observatory stating that the submitted cassette showed no obvious computer-generated effects but lacked enough reference data to identify the object.
This is not an official TUBITAK-hosted copy, so provenance and translation require caution; absence of obvious CGI does not exclude a distant ship, optical effect or other ordinary source.