If they were for some reason doing `npm install` rather than `npm ci`, then `npm install` does update packages in the lock file. Personally I always found that confusing, and yarn/pnpm don't behave that way. I think most people do `npm ci` in CI, unless they are using CI to specifically test if `npm install` still works, which I guess maybe would be a good idea if you use npm since it doesn't like obeying the lock file.

Since nobody else answers your question:

> Do they just mean package.json here?

Yes, most likely. A package-lock.json always specifies an exact version with hash and not a "version X or newer".

> Is that possible?

This comes up every time npm install is discussed. Yes, npm install will "ignore" your lockfile and install the latest dependancies it can that satisfy the constraints of your package.json. Yes, you should use npm clean-install. One shortcoming is the implementation insists on deleteing the entire node_modules folder, so package installs can actually take quite a bit of time, even when all the packages are being served from the npm disk cache: https://github.com/npm/cli/issues/564