(Initially, I made the mistake of asking over at the Manjaro forums. Unfortunately, they seem to be interested in little more than being a way to trap and lynch anyone who ever has the nerve to ask a question to anything other than a search engine (which begs the question of why they're even bothering to begin with...). So I'm trying here instead, hoping for, if not better luck, then at least a lack of a**hats...)

I'm interested in filing a regression ticket for a KDE component. Exactly what "project" or "component" or "package" or whatever, I do not know - I'm not familiar with how KDE is internally organized and how fine-grained the sub-projects go w/r/t issue tracking. But the regression involves the date/time display being absurdly large when mounted on a vertical panel, as of a recent update. (Much like how many of the panel widgets used to be on vertical panels back in early releases of v5).

So if KDE is interested in having me file a ticket, then if they can point me to the tracker for the appropriate sub-project, I'd certainly be willing to do so.

https://bugs.kde.org is the place to file everything, bugs, regressions, feature requests, etc.
Just make sure you stick to one item per report, else this is impossible to trace.

FWIW: this will be moved to the Plasma 5 section, and there is a "plasmashell" component in the bugs system. The forum is meant mostly for user support