Remove -u option

components/config/opts.rs

@@ -612,12 +612,6 @@ pub fn from_cmdline_args(mut opts: Options, args: &[String]) -> ArgumentParsingR
         "7000",
     );
     opts.optopt("", "resolution", "Set window resolution.", "1024x740");
-    opts.optopt(
-        "u",
-        "user-agent",
-        "Set custom user agent string (or ios / android / desktop for platform default)",
-        "NCSA Mosaic/1.0 (X11;SunOS 4.1.4 sun4m)",
-    );
     opts.optflag("M", "multiprocess", "Run in multiprocess mode");
     opts.optflag("S", "sandbox", "Run in a sandbox if multiprocess");
     opts.optopt(