Yeah, that repository's README is a little bit outdated.

Here's what I found works or is broken in macOS Catalina and above:

Works: --------------------

  # Preview source code files with syntax highlighting (like colored .JS files)
  brew install qlcolorcode

  # Preview Markdown files
  brew install qlstephen 

  # Preview JSON files with syntax highlighting
  brew install quicklook-json 

  # Preview plaintext files with unknown extensions, like README, CHANGELOG, etc.
  brew install qlstephen 

  # Preview the content of .IPA files
  # Installs inside /Applications folder
  brew install suspicious-package 

  # Preview iOS/macOS provisioning information for .ipa and .xcarchive
  # For 'mobileprovision' files, Xcode has Quick Look plugin collision:
  # https://github.com/ealeksandrov/ProvisionQL/issues/20
  brew install provisionql 

  # Preview the content of macOS apps
  # Installs inside /Applications folder
  brew install apparency 

  # Preview WebP images
  brew install webpquicklook

Broken: --------------------

  # Display image size and resolution in windo titlebar of Quick Look
  # Doesn't work due to API change from Apple
  # https://github.com/Nyx0uf/qlImageSize/issues/45#issuecomment-610852166
  #brew install qlimagesize 
  
  # Preview Adobe ASE color swatch files from Photoshop, Illustrator
  # Doesn't work in macOS Catalina
  #brew install quicklookase 
  
  # Preview the content of Android .APK files
  # Doesn't work in macOS Catalina
  #brew install quicklookapk

As listed in the README, you also need to unset the quarantine attribute. To see the changes, you need to restart the Quick Look Server after the install, and sometimes requires logging out and in again. Here's a script I made, let me know if it works for you:

https://github.com/spiritphyz/Save-the-Environment/blob/main...

CSV, markdown, plaintext, and JSON plugins are must-haves for office work.

BetterZip's plugin is okay.

Even better would be:

I'd sacrifice my first born child for a "Show Package Contents" option supporting zip, webarchive, and other common composite files.

(Using Finder: highlight file with .app or .dmg extension, right-click to show context menu, chose "Show Package Contents", opens new tab with selected file as "mount" point. I'd really like to know how Finder "mounts" composite files without using fuse file system thingie. Then maybe we could write plugins.)

Because they’re not really “composite files”, they’re packages. It’s just a normal directory with a bit set to treat it as a file in context (also driven by file extension). “Show Package Contents” just opens a Finder window rooted within the package. From CLI you’ll see them as a directory.

Aha. Feeling dumb that I didn't know that. Of course they're directories with some metadata. Duh.

I always kinda guessed that DMGs were something like a ZIP file. Well, not really:

"3. Mounting DMGs

DMGs can be mounted, just like any other file system, though technically this is what is known as a "loopback" mount (i.e. a mount backed by a local file, rather than a device file)"

http://newosxbook.com/DMG.html

Pretty cool. Thanks for the tip.

Now wondering about differences between loopback mount, FUSE, potential for seamless Finder UX integration...