This looks like a great command line alternative to git diff or diff, but I have to admit that I greatly prefer meld when I need a quick diff against non version controlled files, or sublime merge when using revision controlled files.
I use Sublime Merge pretty much every day, and it's nothing short of fantastic.
It's properly fast, the diff/stage/commit/etc UX is excellent. I particularly enjoy how straightforward it makes it to hand-pick lines from multiple files really quickly. The interface abstracts over enough of the Git ux/api to make it get out of your way, but in a way that doesn't make what it's doing a mystery or too out of your control - hovering over a button will often yield the equivalent git cli commands for example.
Personal preference here, but it's also not an electron app, so it's very resource light.
Worth pointing out that this is not mutually exclusive with the article. You can use both, the article (when combined with this pager) will affect what appears inside the chunk header.
FWIW, it looked great on paper/Github, so I installed and tried it. The colors just overwhelmed me, so I had to uninstall it.
Thinking "perhaps, it's just the default color scheme", I installed it again and tried the `delta --show-syntax-themes` command to see the themes in action. Didn't like any of them. So uninstalled it again.
(Delta author here.) You can disable syntax highlighting, either by customizing the {plus,minus}-*-style options to not use 'syntax' as the foreground color, or by selecting the diff-highlight or diff-so-fancy emulation modes. That would allow you to still have some of the other features if they are attractive to you, such as side-by-side view, line numbers, restructuring and streamlining of the default diff format output, copyable code (no +/- characters), etc.
https://github.com/dandavison/delta
It also offers contextual information as well as side-by-side diffs. For syntax highlighting, it uses the same as bat (the cat clone).