NFO Viewer is a simple viewer for NFO files, which are "ASCII" art in the CP437 codepage. The advantages of using NFO Viewer instead of a text editor are preset font and encoding settings, automatic window size and clickable hyperlinks.
NFO Viewer is packaged for most of the popular distros, so easiest is to install via your distro's package management. If not packaged for your distro or you need a newer version than packaged, read below on how to install from Flatpak or the source code.
Stable releases are available via Flathub.
The development version can be installed by running command make install under the flatpak directory. You need make, flatpak-builder
and gettext to build the Flatpak.
NFO Viewer requires Python ≥ 3.2, PyGObject ≥ 3.0.0 and GTK ≥ 3.12. You also need a font that supports the kinds of glyphs commonly used in NFO files: Cascadia Code is a good choice and used by NFO Viewer by default, if available. During installation you will also need gettext. On Debian/Ubuntu you can install these with the following command.
sudo apt install fonts-cascadia-code \
gettext \
gir1.2-gtk-3.0 \
python3 \
python3-gi
Then, to install NFO Viewer, run command
sudo python3 setup.py install --prefix=/usr/local
Windows installers are built irregularly, see releases.