doc(webi-essentials): clarify as per feedback in #768

webi-essentials/README.md

@@ -5,16 +5,74 @@ tagline: |
   The Webi Essentials are curl, git, tar, wget, xz, zip, & webi shell integrations
 ---
 
-### Cheat Sheet
+## Cheat Sheet
 
 > Even Webi needs a place to start.
 
 This installs the tools that are commonly needed to download and unpack various
 packages, using the native package manager.
 
-**This requires root or `sudo`**
+This requires **root or `sudo`** for `apt` or `apk` on Linux.
 
-### Linux (Debian, Ubuntu)
+## Table of Contents
+
+- Files
+- Manual Install
+  - macOS
+  - Linux
+  - Alpine
+  - Windows
+
+### Files
+
+These are the files / directories that are created and/or modified with this
+install:
+
+```sh
+# macOS
+/Library/Developer/CommandLineTools/
+/Library/Apple/usr/libexec/oah/libRosettaRuntime
+
+# macOS & Windows
+~/.local/bin/xz
+~/.local/bin/unxz
+
+# Windows
+~/.local/opt/git/
+
+# Linux
+/usr/bin/git
+```
+
+### How to Install Manually
+
+Most of these utilities are either built-in or provided by the native package
+manager.
+
+Webi makes it easy to automate across a wide variety of development systems, but
+if you wanted to automate for a specific system, you could do so in a much
+simpler way - because you don't have to worry about autodetection or fallbacks
+😉.
+
+So here's how to do that for each:
+
+#### macOS
+
+- Rosetta
+  ```sh
+  softwareupdate --install-rosetta --agree-to-license
+  ```
+- Command Line Developer Tools (incl. `git`)
+  ```sh
+  xcode-select --install
+  ```
+- `xz`
+  ```sh
+  curl https://webi.sh/xz | sh
+  ```
+  See <https://github.com/therootcompany/xz-static>.
+
+#### Linux (Debian, Ubuntu)
 
 ```sh
 sudo apt update
@@ -27,7 +85,7 @@ sudo apt install -y \
     zip
 ```
 
-### Alpine (Docker)
+#### Alpine (Docker)
 
 ```sh
 sudo apk add --no-cache \
@@ -38,3 +96,22 @@ sudo apk add --no-cache \
     xz \
     zip
 ```
+
+#### Windows
+
+`curl.exe` and BSD `tar.exe` are included as part of Windows 10+ - so there's no
+needfor `wget` or `zip`.
+
+- `git`
+
+  ```sh
+  curl.exe -A MS https://webi.ms/git | powershell
+  ```
+
+  See <https://github.com/git-for-windows/git/wiki/MinGit>
+
+- `xz`
+  ```sh
+  curl https://webi.sh/xz | sh
+  ```
+  See <https://github.com/therootcompany/xz-static>.