HelpButton in .src file
	   -> vcl/source/control/button.cxx (HelpButton::Click)

    if ( !GetClickHdl() )
    {
        Window* pFocusWin = Application::GetFocusWindow();
        if ( !pFocusWin )
            pFocusWin = this;

        HelpEvent aEvt( pFocusWin->GetPointerPosPixel(), HELPMODE_CONTEXT );
        pFocusWin->RequestHelp( aEvt );
    }

-> vcl/source/window/window.cxx (RequestHelp)
    + several cases ->

	    ULONG nStartHelpId = GetHelpId();
            if ( !nStartHelpId )
                nStartHelpId = HELP_INDEX;
            Help* pHelp = Application::GetHelp();
            if ( pHelp )
                pHelp->Start( nStartHelpId, this );

Application::GetHelp
    + gets impl. from sfx2/source/appl/app.cxx (SfxApplication::GetOrCreate):
            SfxHelp* pSfxHelp = new SfxHelp;
            Application::SetHelp( pSfxHelp );

    + sfx2/source/appl/sfxhelp.cxx:
	    + ::Start( nId, this )
		+ creates URL: (CreateHelpURL_Impl) :
		        aHelpURL = String::CreateFromAscii("vnd.sun.star.help://");
			aHelpURL += aModuleName;

			if ( !nHelpId )
			    aHelpURL += String::CreateFromAscii("/start");
			else
			{
			    aHelpURL += '/';
			    aHelpURL += String::CreateFromInt64( nHelpId );
			}

window2.cxx:1482:ULONG Window::GetHelpId() const { return mpWindowImpl->mnHelpId; }
	overridden for menu, toolbox etc.

window.cxx (Window::ImplLoadRes): SetHelpId,
	   'GetLongRes' - the 1st item from the resource.

ie. the HelpId is prolly on the window eg.

sfx2/source/doc/doc.src
QueryBox MSG_QUERY_LOAD_TEMPLATE
{
    BUTTONS = WB_YES_NO ;
    DEFBUTTON = WB_DEF_NO ;
    HelpId = MSG_QUERY_LOAD_TEMPLATE;
...



Specific case:
    ModalDialog RID_DLG_ALIEN_WARNING:
        HelpId = HID_WARNING_ALIENFORMAT;

sfx2/source/inc/helpid.hrc:
#define HID_START                   32768
#define HID_SFX_START               (HID_START+300)
#define HID_SEARCHDIALOG 			    (HID_SFX_START + 311) = 33379
#define HID_WARNING_MACROSDISABLED                  (HID_SFX_START + 319)
#define HID_WARNING_ALIENFORMAT                     (HID_SFX_START + 320)
			== 32768 + 620 = 33388

cf.  helpcontent2/helpers/hid.lst:3894:HID_SEARCHDIALOG 33379
     [ no entry for ALIENFORMAT - we have 'Macros disabled' though ]