rustls requires using a matching version of webpki-roots that uses the same webpki types. Numerous library crates that build on rustls often have feature flags to enable one or both of rustls-native-certs or webpki-roots, and then do the same code sequence to add those roots to the rustls client config. Users of those library crates in turn need to request such features, and then enable them in the library crate.

Would it potentially be reasonable to add a feature flag to rustls, which when set, causes rustls to automatically add webpki-roots to the client config? That would allow numerous library crates building on rustls to drop their code doing so, and prevent many more such library crates from needing to add their own options for that. Instead, users of such library crates can just enable the appropriate feature flag in rustls to get the behavior they want.