I found another "poxleber"

[Bernd]

The title
Ein Klegliche Botschafft an Babst die Selmes betreffendt, welche kranck ligt und wil sterben

literally means:
A woeful message to the pope concerning the Catholic Mass which is lying sick and wants to die
It's a joke on the Catholic church system, brandishing it as corrupt and full of hypocrisy. This is a reformation work in the style of Martin Luther and actually quite funny. You gotta read it like a comedy sketch including laughter from the audience. The joke here is that the Catholic Mass is presented as a sick and dying person with Pope and Cardial musing how to save her (but mostly themselves).

The box leber section means the following:
The cardinal reports to the pope that the institution of the Catholic Mass is sick and awaiting death as if he was talking about a person. Saying that if she dies their comfortable life will be over and they'll have to give up their fat whores as well (yes literally).

The pope replies asking is she (the Catholic Mass) can't be saved by a warm bath or a good syrup. Goddamned, whatever it takes, we'll spare no expenses!