These are not Sitecore patch config files, and as such they are not read by the Sitecore Configuration Factory, so nothing has changed in that regard with only
.config files being loaded.
If you inspect the contents of the config files using Notepad, you'll notice they are all changes that should be applied to the
This is not patching a
<sitecore> section of the config, it's targeting an element in the root
web.config. This is automatically applied by a post-install step when you install the JSS and SXA packages respectively:
In each of these post-install steps there is a method which checks for all
.sxaconfig files within the
/App_Config folder and applies the required changes to the
web.config. Once you have installed the packages, you should check the
web.config to ensure that the relevant changes have been applied.
NOTE: If you have checked in the stock
web.config into your source code, then you should ensure that these changes have also been applied. Unlike some earlier modules, the fact that these
web.config changes are required is not mentioned in any of the documentation.