In short: it makes HoMM V behave like a modern title.
Inside the Profiles folder, look for a file named (for Tribes of the East) or autoexec.cfg (for the base game). heroes 5 widescreen fix
If the software fixes fail, or if the game runs but looks stretched, you need to adjust your graphics card settings. This forces your monitor to handle the image scaling rather than the game engine. In short: it makes HoMM V behave like a modern title
Find the line setvar gfx_resolution and change it to your monitor's native resolution, such as 1920x1080 . such as 1920x1080 .