Special weapons are weapons that are not part of the unit inventory, for example ALIEN_PSI_WEAPON or STR_LOBSTERMAN_MELEE_WEAPON.
Until now, these weapons were not saved in the savegame.
Since OXCE v7.0, these weapons are also saved.
This means you can make limited-use special weapons (without resetting the remaining ammo when reloading the game), or use script tags.
The saves are backwards-compatible with older OXCE versions and also with OXC.