Seems strange that the dev seems to be keeping quiet on this, no?
the issue was just posted 7 hours ago. maybe they just haven't seen it yet.
someone in issue #573 asked if the dpapi file is really needed, and by looking at the manual installation instructions, yes, because that contains all the code.
the developer loads custom code into the spotify process by using such an "override" dll file. it works because spotify is voluntarily loading a dll with this name, and if there's such a file in the directory besides the .exe file, it'll take precedence over the original file installed in the system.
the trojan warning is probably triggered because this technique is often used by malware to change the behaviour of your programs, but as with most technologies, it has good uses too