The original source tarball for Evis version 2.2_0, unmodified, is in Files.
README.txt gives tips for compiling on modern compilers (gcc-4.4.5 / linux) and using Xcode for Apple Sierra OS.
Elvis is a vi(1) (visual ed) vi editor clone (vim is another clone). "vi" is short for "visual ed(1)" (the 1 means see manpage for ed in section 1 of unix manual pages). vi as a visual editor means typical keyboard editing with ed(1) accessible to do complex editing jobs that developers often...
Source Navigator NG is a source code analysis tool.
With it, you can edit your source code, display relationships between classes and functions and members, and display call trees.
You can navigate your source code and easily get to declarations or implementations of functions, variables and macros (commonly called "symbols") which helps you discovering and mapping unknown source code for enhancement or maintenance tasks.