Setting package.json: dependencies or devDependencies?

Question

Building projects

Hello.
A question that has been haunting me for quite some time now. So far I've been solving it for myself mostly on a whim, but it's time to figure it out.
The point is this. Let's say I have a project that is built by webpack, it uses a group of babel packages (core, polyfill, preset), plugins for webpack itself, including bundle-analyzer. Many mans write that webpack needs to be added to devDependencies: they say that the assembly has nothing to do with production, it's development. In my understanding, only bundle-analyzer, which is used only in the development process, belongs to development, but webpack should be in dependencies, because otherwise I won’t be able to assemble the prod assembly by first installing the dependencies, for example, with the command
yarn install --prod
(in my case, the assembly takes place on the gitlab-ci side).
Actually, a request to connoisseurs: help me dot all the i's in my head and finally figure out when a package should be included in dependencies, and when in devDependencies.