If detectPeopleACF is an m-file, then you can just use
at the command line to view the code.
Type is a FAR better choice than using edit. Some will suggest you use edit, but it is too easy to mistakenly change code, typing a character someplace at random without realizing you did that. Then worse, you will accidentally save the file. Yeah, like you would NEVER do that. People do. Then you will have a bug in your code, as the file will no longer run properly.
So use type to view code!
If the code has nothing visible in it when you try that beyond some lines of help, then it is compiled code or a p-file. You CANNOT view compiled code or p-files.