Kbase Article of the Week: Mac OS 8: Appearance Manager Information →

Apple Support:

The Appearance Manager, introduced with Mac OS 8, modifies the appearance of the original Finder to include options for changing menu fonts, window-shading (collapsable window title bars), and other appearance-centric features. The Appearance Manager is now considered an integral part of the Mac OS, and is installed as part of an “Easy Install” process.

Seemed appropriate after talking about macOS Mojave’s Dark Mode this week.