How does this simple patch work?

After unzipping moz2_0.zip and using the Java disassembler on netscape.applet.AppletSecurity, the following code catches your eyes:

public class netscape.applet.AppletSecurity extends java.lang.SecurityManager {
...
    int networkMode;
    static final int NETWORK_NONE = 1;
    static final int NETWORK_HOST = 2;
    static final int NETWORK_UNRESTRICTED = 3;
...
Method void reset()
   0 ldc #15 <String "appletviewer.security.mode">
....
  22 aload_0
  23 iconst_3
  24 putfield #84 <Field netscape.applet.AppletSecurity.networkMode I>
  27 return
  28 aload_1
  29 ldc #29 <String "none">
  31 invokevirtual #108 <Method java.lang.String.equals(Ljava/lang/Object;)Z>
  34 ifeq 43
  37 aload_0
  38 iconst_1
  39 putfield #84 <Field netscape.applet.AppletSecurity.networkMode I>
  42 return
  43 aload_0
  44 iconst_2
  45 putfield #84 <Field netscape.applet.AppletSecurity.networkMode I>
  48 return

All the patch does is to replace statements 38 and 44 with iconst_3 (opcode 0x06) - thus making sure NETWORK_UNRESTRICTED is written in AppletSecurity.networkMode. Note that reset() is called in the constructor of the security manager.
Direct patching of moz2_0.zip is possible since the .class files are stored in the zip file due to their small length.

That's all there is to it.