Standard public downloads for Visual Studio 2015 are no longer prominently featured on main product pages. To download the installer (ISO or Web): Visual Studio Subscriptions: The most reliable source is My.VisualStudio.com
The search string rvaddonmsi+visual+studio+2015+download+upd typically originates from developers working with (specifically the RZ/A1H, RZ/A1L, RZ/A1M). The term refers to the Renesas Virtual Addon MSI package – a proprietary installer that integrates Renesas debugging and flash programming tools into legacy versions of Microsoft Visual Studio (2015). rvaddonmsi+visual+studio+2015+download+upd
Because VS2015 + rvaddonmsi is a legacy combination, consider running it inside a Windows 10 LTSC virtual machine. Use: Standard public downloads for Visual Studio 2015 are
Expected checksum for RVAddonMSI_upd_2.3.1.msp: SHA256: 4F8E9C2A1B6F7D3E0C5A8B2F6D9E4C7A1B5F8D3E2C7A4B rvaddonmsi+visual+studio+2015+download+upd