Based on details found via Patreon and community discussions, here is a look at what the file likely contains:
The filename refers to a compressed archive of a specific Japanese adult indie game or doujin title, likely sourced from DLsite , where "RJ" codes serve as unique product identifiers. In this case, the code RJ01009285 corresponds to a title developed by the circle Xenote , titled "Icha Rabu Akaibu" (roughly translated as Lovey-dovey Archive ). Key Features of the Title H-RJ01009285.rar
You will need a utility like WinRAR or 7-Zip to open it. Based on details found via Patreon and community