Created by: perrin4869
Reading through issues, https://github.com/twbs/bootstrap/issues/23204 where it was decided to make jQuery and popper.js peer dependencies, I think that the main reason for the decision was to minimize the number of packages installed by npm. However, peerDependencies are required too, and emit a warning if they are not found... they are not really optional, so it does not solve the problem.
Also, peer dependencies are mostly designed for cases like when using react-router, you will inevitably be using react too... but in this case, chances are that even if you use bootstrap, you will not be using those other 2 dependencies on their own.
Moreover, both jQuery and popper.js are marked as external in https://github.com/twbs/bootstrap/blob/v4-dev/build/rollup.config.js, so they are not really bundled in. In a way they could even be considered devDependencies, because neither package is used in practice... but in principle they are imported in the source files, so they are technically normal deps.
This is not a breaking change, since it does not change the usage of the package in any way.