[Libreoffice] A few questions for developers

Hello!

I found that images as a resource defined in *.src file with parameter 
«MaskColor»:

Image RID_SVXBMP_SLIDERINCREASE
{
    ImageBitmap = Bitmap
    {
        File = "slidezoomin_11.png" ;
    };
    MaskColor = STD_MASKCOLOR;
};

What does this parameter mean? Can I don't set MaskColor?


I found that some functions/methods is never used.  This functions are 
listed in «unusedcode.easy 
<http://opengrok.libreoffice.org/xref/core/unusedcode.easy>» file. Is 
this file generated automatically or I should modify it in case of 
removing unused functions?


How can I generate a patch (diff) which may be used to push changes to 
official repository? Should I make a commit to a local repository before 
generating a patch? And what I should do in case of modification of 
binary data (changed/added images)?

Thank You!

--
Best Regards,
    Dmitry

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fn:Dmitry Ashkadov
n:Ashkadov;Dmitry
email;internet:dmitry.ashkadov@gmail.com
note:JID: dmitryash@jabber.mipt.ru
version:2.1
end:vcard