So here's the state of WebKit on FreeBSD, from the KDE-FreeBSD perspective (and a little bit about the GTK ports, too).
- Qt4 WebKit is doubly unmaintained; Qt4 is past its use-before date, and its WebKit hasn't been meaningfully updated in years. It is also, unfortunately, the WebKit used in the only officially available KDE ports, so (e.g.) rekonq on FreeBSD is the KDE4 version. Its age shows by, among other things, not even rendering a bunch of current KDE.org sites properly.
- Qt5 WebKit port has been updated, just this weekend, to the annulen fork. That's the "only a year and a half behind" state of WebKit for Qt5. The port has been updated to the alpha2 release of annulen, and should be a drop-in replacement for WebKit for all ports using WebKit from Qt5. There's only 34 ports using Qt5-webkit, most of them KDE Applications (e.g. Calligra, which was updated to the KF5-version some time back).
- Webkit1-gtk2 and -gtk3 look like they are unmaintained,
- Webkit2-gtk3 looks like it is maintained and was recently updated to 2.16.6 (latest stable release).
So .. the situation is not particularly good, perhaps even grim for Qt4 / KDE4 users (similar to the situation for KDE4 users on Debian stable). The transition of KDE FreeBSD ports to Qt5 / Frameworks 5 / Plasma 5 and KDE Applications will improve things considerably, updating QtWebKit and providing QtWebEngine, both of which are far more up-to-date than what they are replacing.