SlackBuildsOrg/games/homm3_shareware_data

Heroes of Might and Magic III: The Restoration of Erathia Demo

In Heroes III, you control the actions of heroes to complete mission
objectives in a variety of conflicts taking place in the mythical land
of Erathia. As heroes travel across the land with their armies, they can
explore, seek artifacts, and find treasure, as well as lead their armies
into battle. Towns can also have armies garrisoned for their defense and
act as centers for recruitment, learning of magic spells and trading.
Towns you conquer become part of your territory. You may develop your
towns to provide yourself with offensive, defensive, and logistical
advantages.

This repackages the demo game data and makes it ready to use with the
VCMI Heroes III engine that runs natively on Linux. The demo for Mac is
used, since it is supposedly more complete than the one for Windows
(which does not seem to work with VCMI). For more info, check this
discussion:
https://forum.vcmi.eu/t/support-for-demo-versions/1079/17

The package installs the data system-wide and the game is playable and
will give you an idea about how VCMI works, however there are graphics
glitches and probably other problems. Consider buying the full game.