If you build packages yourself, one can either include debug info, or generate a split package that includes debug info.
The piece that may still be missing is the inclusion of source code in debug packages, which is necessary to get any context for a debug session (it is not sufficient to seek out and clone random git repos because of versioning & patching differences).
But ideally, there would be a `-debug` package for every package in arch's repos, and one would not need to build them manually when debug symbols are needed. Arch does not have this.
It is, in linux distros at large. Arch, however, does not publish (or even generate) those debug files (which contain the debug info & symbols that were stripped out).
https://bbs.archlinux.org/viewtopic.php?id=174250
https://bugs.archlinux.org/task/10975
https://wiki.archlinux.org/index.php/Debug_-_Getting_Traces
still not clear if it was ever implemented