Generally increasing the quality of our software through more automated testing and QA is a part of what this is all about.

As a counterpoint to KDE's light weight, on my system right now, plasmashell alone is eating 584 megabytes, and I've seen over 1 gigabyte in the past. Googling plasmashell memory usage turns up countless reports of memory leaking. From what I've heard, you can try removing applets and seeing if the leak stops, but this is involved, takes a long time to know for sure that plasmashell doesn't leak, and it's difficult to restore your original configuration. I tried using Heaptrack in the past, but IIRC the call stack of the leaked allocations pointed to the internals of the QV4 JavaScript engine, rather than the QML code triggering those allocations.

Is this goal close enough to my idea of "ensure stability, reliability, and predictable behavior, and eliminate crashes and memory leaks in apps like baloo, plasmashell, and plasma-systemmonitor, eg. through better-documented invariants enforced through debug and release assertions?"