should mean that the command is not displayed for PDFs nor for any audio file.
What it actually does is display the command for both because the algorithm is wrong - since an audio file is not a PDF, it displays, and since a PDF is not an audio file, it displays.
The algorithms wrongly check that the selected files match any one rule, whereas they should be more sophisticated - they should match any positive rule and none of the negative rules.
E.g. the following mimetype "not" rules:
should mean that the command is not displayed for PDFs nor for any audio file.
What it actually does is display the command for both because the algorithm is wrong - since an audio file is not a PDF, it displays, and since a PDF is not an audio file, it displays.
I'm working on it!