This format was developed to simplify use of Type1-fonts in some software. It’s 8-bit and so it’s quickly processed by programs and it has a compact structure. PFB contains additional metadata. Besides the storage of system fonts, a good example of its use is its application in AutoCAD to create font files with compilation.
This format is used to store templates and designs in PageMaker 3. PT3 allows for a set of font descriptions, and for the layout and graphical elements to be stored in PostScript Type 3 format. This container is used as an editable file to meet publishing needs, and was created in a program for the PageMaker layout.