Programmers can write and integrate their own UNO (Universal Network Objects) components to Office. Those new components can be added to the Office menus and toolbars; we call them "Add-Ons".
The integration of new components is supported by some tools and services. Details can be found in the Office Developer's Guide. The three main steps are as follows:
Register the new components within Office. This can be accomplished using the tool unopkg, which can be found in {installpath}/ </span>program.
Integrate the new components as services. The ProtocolHandler and JobDispatch services assist you; more information can be found in the Office Developer's Guide.
Change the user interface (menus or toolbars). This can be done almost automatically by writing an XML text file that describes the changes. More information can be found in the Office Developer's Guide.
The Add-Ons can extend the functionality of Office. They are not related to the Add-InsAdd-Ins that provide new functions for Office Calc.