An HPGL(Hewlett-Packard Graphics Language) file contains an instruction set for plotter control, developed by Hewlett-Packard. Hewlett-Packard plotters use this file to draw and print vector and raster content on the paper.
Files with DOTX extension are template files created by Microsoft Word to have pre-formatted settings for a generation of further DOCX files. A template file is created in order to have specific user settings that should be applied to subsequent files created from this template. These settings include page margins, borders, headers, footers, and other page settings. Such templates are used in official documents such as company letterheads and standardized forms.
You can also convert PLT into many other file formats. Please see the complete list below.