Why do Facebook posts show "Published by DrumUp" message?

When posting on Facebook, you will notice the "Published by DrumUp" tag; something like this screenshot below of a post on our own Facebook page:

This is OK!  Because if you however on the little question mark next to that tag, you will see this popup message: "Only people who manage this page can see this message"

So the general audience do not see this message and only those members from your team who have admin, owner etc. access to your facebook page will see the message.

At this time, this tag is required as part of Facebook's API agreement with all third party companies such as DrumUp. This tag is only visible for page owners and not to regular audience. 

If we navigate to the same page as a different user (a general facebook user), you can verify that the "Published by" tag is not visible anymore, as in the screenshot below: