没有设置 Homebrew 清华源， brew 却从清华源下载？

过程

 % brew search iina
==> Formulae
inja

==> Casks
iina                                                                                                            iina-plus

 % brew install iina
==> Downloading https://dl-portal.iina.io/IINA.v1.3.2.dmg
==> Downloading from https://mirrors.tuna.tsinghua.edu.cn/iina/IINA.v1.3.2.dmg
######################################################################################################################################################################################################################## 100.0%
==> Installing Cask iina
==> Moving App 'IINA.app' to '/Applications/IINA.app'
==> Linking Binary 'iina-cli' to '/usr/local/bin/iina'
🍺  iina was successfully installed!

查看 brew 配置

 % brew config
HOMEBREW_VERSION: >=2.5.0 (shallow or no git repository)
ORIGIN: (none)
HEAD: (none)
Last commit: never
Core tap origin: https://github.com/Homebrew/homebrew-core
Core tap HEAD: (none)
Core tap last commit: never
Core tap branch: (none)
Core tap JSON: 15 Jul 17:28 UTC
HOMEBREW_PREFIX: /usr/local
HOMEBREW_API_AUTO_UPDATE_SECS: 86400
HOMEBREW_CASK_OPTS: []
HOMEBREW_MAKE_JOBS: 4
Homebrew Ruby: 2.6.10 => /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.10_1/bin/ruby
CPU: quad-core 64-bit broadwell
Clang: N/A
Git: N/A
Curl: 7.87.0 => /usr/bin/curl
macOS: 12.6.7-x86_64
CLT: N/A
Xcode: N/A

 % brew tap
elastic/tap
gcenx/wine
homebrew/cask
homebrew/core
homebrew/services

属实给我整不会了

仔细想想以前有可能临时用过清华的源，但是并没有配置环境变量啊