@SuppressWarnings( "MixedMutabilityReturnType" ) // Error Prone
	private static List<String> readConfig( String filename ) {
		File userHome = new File( System.getProperty( "user.home" ) );

		// search for config file
		String[] configDirs = {
			".config", // KDE 5
			".kde4/share/config", // KDE 4
			".kde/share/config"// KDE 3
		};
		File file = null;
		for( String configDir : configDirs ) {
			file = new File( userHome, configDir + "/" + filename );
			if( file.isFile() )
				break;
		}
		if( !file.isFile() )
			return Collections.emptyList();

		// read config file
		ArrayList<String> lines = new ArrayList<>( 200 );
		try( BufferedReader reader = new BufferedReader( new InputStreamReader(
			new FileInputStream( file ), StandardCharsets.US_ASCII ) ) )
		{
			String line;
			while( (line = reader.readLine()) != null )
				lines.add( line );
		} catch( IOException ex ) {
			LoggingFacade.INSTANCE.logConfig( "FlatLaf: Failed to read '" + filename + "'.", ex );
		}
		return lines;
	}
Gets the default font for KDE from KDE configuration files.

The Swing fonts are not updated when the user changes system font size
(System Settings > Fonts > Force Font DPI). An application restart is necessary.
This is the same behavior as in native KDE applications.

The "display scale factor" (kdeglobals: [KScreen] > ScaleFactor) is not used
KDE also does not use it to calculate font size. Only forceFontDPI is used by KDE.
If user changes "display scale factor" (System Settings > Display and Monitors >
Displays > Scale Display), the forceFontDPI is also changed to reflect the scale factor.
flatlaf-core/src/main/java/com/formdev/flatlaf/LinuxFontPolicy.java