Depending on what you are searching for the only way to find a “hardcoded” user is to scan the source. This is not to bad if you use PDM. Go to the source library and put a 25 in the first source member, then shift + F1 to auto fill all members. Hit enter and for the search enter single quote, single quote, name, single quote,single quote. Then hit enter again and it should find all the hardcoded occurrences. Do this for each source code library.
This just popped in, if they are hardcoded as a table defined with the program the perform the search without the quotes. In cases like this it’s best to have the list of users in a file or table for reference. That way the is no recompile necessary if a change is needed.