How my Direct Update DSO is getting loaded?

Hi experts,

I have few direct update DSO's developed by someone else. I just wanted to know how these direct update DSO's are getting loaded. I have serached SCN, there some answers which are not satisfactory.

1) When a direct DSO is laoded via APD, do we have any straight way to find the relevant APD name, if so , what is that?

       (My understanding is , we can search in T code RSANWB with DSO tech name)

2) What is other way loading Direct DSO, if its are API's, how to find those API's? and what these API do and how they work

3) else if a programme is loading , then how to find the programme name. (My understanding is, take active table from direct DSO and look for where used list,)

please share your valuable inputs, just wanted to clear some air around Direct DSO's.

Thank You in advance

Harikrishna