buttonIconId
From SAP Enable Now Wiki
Scope
Web Assistant parameter, specified either in the URL or in the Web Assistant parameters in the linked application.
Purpose
This parameter can be used to specify an alternative icon to use for the Web Assistant help button on the Fiori taskbar. This is helpful if the application already has a 'help' icon that looks like the default Web Assistant icon.
This parameter only works with SAP Fiori-based systems.
Usage
Specified as:
buttonIconId={icon name}
where {icon name} is the name of the icon in the SAP IconFont set of icons.