Uses its own scripting language (Avenue) for customization, which is completely different from the Python used in modern ArcGIS Pro.
If you need a portable GIS but want modern security and features, consider these alternatives: Why ArcView 3.x is Still in Use - Geography Realm Arcview Gis 3.3 Portable Free Download-
ArcView GIS 3.3 is a geographic information system (GIS) software developed by ESRI (Environmental Systems Research Institute). It's a popular tool for visualizing, analyzing, and editing geographic data. Although it's an older version, it still has its uses, especially for those who have existing projects or are looking for a free solution. Uses its own scripting language (Avenue) for customization,