I have a large number of cloropeths stored in SLD and QML formats. QGis is unable to apply any of those, there is no option in the GUI for SLD, whereas it fails to apply QML files correctly.
Is there any way to use an externally defined choropleth in QGIS 3? Some way to convert QML or SLD to another format that QGIS understands? Or some plug-in that can apply the SLD standard?
Update I: The screen capture below shows the Load Style dialogue in QGis 3.4. Note that the SLD file is not shown in the list: the dialogue only lists .qml files, since there is no SLD option in the file type dropdown menu. If the SLD file name is inserted manually, the Open button remains greyed out.
Update II: From the comments to the answer below, it is apparent that the Style Load dialogue is different in Windows from what I get on Linux. A discussion is now open at the UbuntuGIS list.
Update III: the screen capture below was obtained in a different system, with QGis 3.10 installed on Fedora 29. As with QGis 3.4 on Ubuntu, the file type dropdown only contains the QML option and only .qml files are listed.
Update IV: the problem reported in this question can be verified with the OSGeo-Live 13 distribution. Load a map from /usr/local/share/data/raster
and then follow Layer Properties > Symbology > Style > Load Style. The dialogue does not list SLD as a possible type, only QML. If an existing QML file is selected it is not applied correctly.