rathole

A technical subject that is known to be able to absorb infinite amounts of
discussion time without more than an infinitesimal probability of arrival at
a conclusion or consensus. That's a rathole (or just Rathole! ) is
considered a pre-emptive bid to change the subject. The difference between
ratholes and religious issues is that a holy war cannot be pre-empted in
this way. Canonical examples are XML namespaces and open-source licensing.