The RFC Editor has asked that we provide a list of items for which there will never be a break around the slash. The test says that PDF⁠/⁠A and S⁠/⁠MIME should not be broken when they occur.

We also deal with the possiblity of some long items such as this⁠/⁠is⁠/⁠a⁠/⁠long⁠/⁠test which will not break either. We only match exact items however so PDF/A/3 will be broken as the algorithm currently stands.

What about addresses: 192.168.20.0/16, 192.168.0.0/24, 192.168.0.0/30, and prefix length indications like /48 /56 /64 /72 /80 /88 /96 and so on? These should not be broken after the forward slash.