This is a rich-text editor same as Apple TextEdit.
[System Requirement]  Mac OS X 10.5 or later is needed for ver.0.3.1.
macOS 12.0 or later is needed for 64bit version.
[Functions]  It supports only rich-text reading and writing. The only function is added to edit printing margins. Some functions are not available, for example, Hyphenation, Page-Break, Auto-Save, Header/Footer, Document-Property Editing, and so on. But, all the data that TextEdit saved including them are reserved correctly.