gtksourceview18
GTK+ 2.0 Source Editing Widget
GtkSourceView is a text widget that extends the standard GTK+ 2.x text widget, GtkTextView. GtkSourceView improves GtkTextView by implementing syntax highlighting and other features typical of a source editor.
There is no official package available for openSUSE Leap 15.5Distributions
SUSE SLE-15-SP1
Unsupported distributions
The following distributions are not officially supported. Use these packages at your own risk.