starting with DB2 10 for z/OS, DBRMs are no longer bound into a plan; the DB2 plan points to a (list of) collection id(s) that, after a successful package bind, contain the questionable DB2 package.
So if your program source code contains any SQL statements, then it's intent is most likely to access DB2 data. During your program compile process, the DB2 precompiler/coprocessor has then, in most cases, created a DBRM, and that DBRM should have been bound to become a DB2 package. Some specific tables of the DB2 catalog can then be queried to find the DB2 package.
To understand this process in more details, you may have a look at chapter Preparing an application to run on DB2 for z/OS
in the Application Programming and SQL Guide. Additionally, there's this famous DB2 (V9) redbook DB2 9 for z/OS: Packages Revisited
to find plenty of information related to plans and packages.