The ServiceWorker static routing API is an API used for routing the request to the network, the ServiceWorker fetch handler, or directly looking up from cache, and so on. Each route consists of a condition and a source, and the condition is used for matching the request. For Chromium implementations, the "or" condition is only the supported condition. However, to write the condition more flexibly, supporting the "not" condition is expected, which matches the inverted condition inside.
When writing a rule without the "not" condition, it gets unnecessary complexed. To proceed something, it should be written as the reversed rule, and the default route should also be set to represent the matching case. If there is multiple rules, writing a condition that won't matches other condition gets extremely difficult. If we introduce the "not" condition, the way to write such inverted rule gets much more easier.