Unlike TrueType fonts (TTF) which are vector-based outlines used across Windows applications, .shx files are specific to AutoCAD. They are compiled from .shp (shape definition) source code into a binary format that AutoCAD can read rapidly.
If you prefer to keep your custom fonts in a separate folder (e.g., on a company server): Xarab.shx Autocad Font
font is a legacy AutoCAD "compiled shape" font specifically designed to display Arabic text in drawings. Because it is an SHX font rather than a TrueType (TTF) font, it functions by mapping standard ASCII English characters to Arabic glyphs. Google Groups Key Technical Characteristics Legacy Mapping Unlike TrueType fonts (TTF) which are vector-based outlines