PROCESSOR-SDK-J7200: is there a document descript the means of file extension likes *.ser5f *.aer5f *.oer5f *.oa72fg *.a72fg

I  am new to  J7200 development , 

I am familiar with  *.o *.so *.a *.lib  *.hex *.elf 

but not understand what is the  file extension  likes  *.ser5f *.aer5f  *.oer5f *.oa72fg *.a72fg

is there a document descript  the means of  file extension  likes  *.ser5f *.aer5f  *.oer5f *.oa72fg *.a72fg?

Thanks !