What do the prefixes in the output of macOS pluginkit mean?

Question

Executing pluginkit --match in Terminal produces the following output (unimportant lines skipped):

+    com.apple.ncplugin.weather(1.0)
-    com.apple.share.SinaWeibo.post(1.0)
  H. com.apple.InternalFiltersXPC(2.0)
     com.apple.ncplugin.FindMyFriends(1.0)
!    com.mycompany.MyDemoPlugIn(1.0)

There is another question with answer about + and - prefixes.

+ com.mycompany.finderExt(1) - If the extension is enabled
- com.mycompany.finderExt(1) - If the extension is not enabled

But what do the exclamation mark ! and H. mean? What does it mean when there is no prefix at all?

Thank you!

Answer 1

! means the Finder Sync extension is not running from the containing app. This is possible if you have multiple copies of the containing app on your system.

You can check extension path using this command:

/usr/bin/pluginkit -m -v -i com.mycompany.finderExt