brew autoupdate showing "Error: Unknown command: autoupdate" on brand new install

[honeybyhomo]

Output of brew config

HOMEBREW_VERSION: 4.2.12
ORIGIN: https://github.com/Homebrew/brew
HEAD: 780fbbc65e90fbe09629aba180a1839e9e7dbaf2
Last commit: 2 days ago
Core tap JSON: 13 Mar 13:00 UTC
Core cask tap JSON: 13 Mar 13:00 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_MAKE_JOBS: 8
Homebrew Ruby: 3.1.4 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.1.4/bin/ruby
CPU: octa-core 64-bit arm_ibiza
Clang: 15.0.0 build 1500
Git: 2.39.3 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 8.4.0 => /usr/bin/curl
macOS: 14.4-arm64
CLT: 15.3.0.0.1.1708646388
Xcode: N/A
Rosetta 2: false

Output of brew doctor

Your system is ready to brew.

Description of issue

Just installed homebrew on a brand new computer. Installed a lot via brewfile (bundle) – everything is working well. But brew autoupdate doesn't work and just says Error: Unknown command: autoupdate

[SMillerDev]

brew autoupdate is an external command and not part of brew. Unless you tap https://github.com/DomT4/homebrew-autoupdate in your Brewfile, it won't be available.

[honeybyhomo]

Ah, I thought that since it's brew autoupdate that it would be part of "standard brew". Thanks!