Is there any valid reason to install Tigerbrew (Homebrew) on a modern Mac OS?

I think it's safe to assume that you were not hacked by someone who then installed Tigerbrew on your computer.

From mistydemeo: Tigerbrew is "A little experimental fork of Homebrew that adds support for PowerPC Macs, and Macs running Tiger (or Leopard)."

So, on the face of it there is no reason to install Tigerbrew on a modern macOS. In fact, there are good reasons to remove it.

But:

1. You don't have a modern macOS and the real Homebrew is fully supported on 10.14 onwards and only best effort on 10.9-10.13

2. Homebrew's installation instructions say "For 32-bit or PPC support see Tigerbrew".

So that gives 2 reasons for you to use Tigerbrew:

1. Homebrew's lack of full support for your version of macOS though it probably would work fine for installing basic unix utilities. On the other hand, Tigerbrew is not intended for more recent than Leopard.

2. You particularly want to install old 32-bit brews.

But, if it were me, I would uninstall Tigerbrew (following instructions from here ) and install Homebrew. See how it goes for you.

Edit: According to current man brew, Misty De Meo is part of Homebrew's Project Leadership Committee. You could ask her via the Tigerbrew GitHub where you can find continuing interest on the Issues page.