The .OBB file or you may say Opaque Binary Blob files are used by the Android Apps which are old online mostly on Google Play Store. OBB lets you store huge files and store them in SDcard so.
That your app and make use of it. An .OBB file contains assets for using the JOBB Tool, which is generally used by Android SDK. These .OBB Files work with various assets of android applications like graphics, sounds and video. Along with this they also hold additional encrypted data like the graphics and also the media files. It is very simple to upload it with APK files by using the Google Developer console. The producer for this type of file format is Google.
In addition to the problem described above, i.e. the lack of the appropriate application to support the .OBB file, there may be several reasons that cause problems with opening and operation of the data format:
A quite common problem is the lack of application in the appropriate version. Even if you have an application, with the help of which you should open the .OBB file, you may have a problem with it because of its version. Perhaps in previous versions the application has not yet supported the .OBB file, so download the update and check again.
If you have already installed the appropriate application, and it is the correct version, the file may not open correctly, because the operating system does not have information that this program supports the file. So you need to "show" which program the computer should use. To do this:
It also happens that the file you want to open is corrupt and therefore there is no such possibility. In this situation, you should find its different version, or ask a person from whom you got, to send it again.