question: private String tweakNativeLaunchUri ( String uri , boolean forDebugging , LaunchInfo launchInfo ) throws IOException , FileNotFoundException { if ( launchInfo . isHttpOrAbout ( ) ) { boolean modify = ( getPreference ( PREF_URI_MODIFICATION ) != 0 ) ; if ( modify && forDebugging && ! launchInfo . isAbout ( ) ) { uri = URLHelper . escapeSpace ( uri ) ; URLHelper urlHelper = new URLHelper ( uri ) ; Map < String , String > params = urlHelper . getParameterMap ( ) ; params . put ( "debug" , "true" ) ; urlHelper . setParameterMap ( params ) ; uri = urlHelper . getURL ( ) ; } } else { File f = null ; if ( uri . startsWith ( "file:" ) ) { try { f = new File ( new URI ( uri ) ) ; } catch ( URISyntaxException e ) { IOException ioe = new IOException ( e . getMessage ( ) ) ; ioe . initCause ( e ) ; throw ioe ; } } else { f = new File ( uri ) ; } if ( f != null && f . exists ( ) ) { uri = f . getAbsolutePath ( ) ; } else { throw new FileNotFoundException ( uri ) ; } } return uri ; }
target:  Tweaks the launch URI if necessary, e.g. may append "?debug=true"