This is Gedit, the default text editor of the GNOME desktop environment. It has been designed as a general purpose text editor. It is mainly focused on simplicity and ease of use user interface.
- Configurable syntax highlighting for various languages. Gedit can habdle source code developed using C, C++, Python, Perl, Java, HTML, XML, ...)
- Provides undo / redo features.
- Allows to edit files from remote locations
- File reverting
- It supports cut, copy and paste functionalities.
- Allows to search and replace using regular expressions
- Texts can be wrapped.
- Provide line numbering.
- Support right margin.
- Bracket matching to facilitate the source code tracking.
- Configurable fonts and colors
- A flexible plugin system.
Further instructions can be found at https://wiki.gnome.org/Apps/Gedit