[mostly OS X]: KDEHOME vs. ~/.kde best practices, *rc files and related questions

[René J.V. Bertin]

Hi,

I have some questions related to where KF5 expects its configuration files and other local stuff, how KF5 and KDE4 applications cohabit (or not) in that aspect, etc.
Some of these are inspired by the fact that I have noticed several weird issues on my Kubuntu KDE4.14 desktop after having run KF5 autotests (modified settings; KF5 installed into /opt/local), but my main focus is OS X; MacPorts to be more specific.

- kdelibs has a built-time define, KDE4_DEFAULT_HOME that is set to ".kde" by default, and also uses $KDEHOME. Kubuntu's Project Neon5 which provided a KF5 environment in a parallel prefix as I plan to do sets $KDEHOME to a directory which indeed appears to host the KF5 equivalent of ~/.kde . However, both strings only occur KCoreAddons::Kdelibs4Migration.
KConfig also has some autotests that contain "kdehome" and "KdeHome".
Does KF5 have the equivalent concept of ~/.kde, or is this something that only certain KF5 applications have (I could see it doesn't necessarily make sense for all KF5 dependents)? Either way, where is that location determined, if it exists?

- Both on OS X (MacPorts) and in my Linux packaging, I'd want my ~/.kf5 (to give it a name) to be independent from KDE4's ~/.kde . An auto-import feature from ~/.kde would be nice, but of secondary importance. For the foreseeable future, I see myself running a select few KF5 applications in an environment mostly populated by KDE4 applications (= under a KDE4 desktop, on Linux). Is there something like a "best practices" scheme for that, and if so, where can I read up on this?
NB: the documentation on api.kde.org is unavailable currently (e.g. http://api.kde.org/frameworks-api/frameworks5-apidocs/kconfig/html/index.html).

- Does KF5 (or do KF5 applications) still use *rc config files, and/or does that depend on the host? I've already seen a few .plist files appear in my ~/Library/Preferences on OS X, binary property lists that are a sort of Apple-specific compiled XML. Does anyone know if that's how KF5 software will store its configuration files and if it is even capable of reading the older *rc files? (Without support for that Kdelib4Migration would seem incomplete, no?)

Thanks for any light you can shed on these issues,
René