[jacobolus]

There is a menu option Go → Enclosing Folder, which clearly lists the keyboard shortcut.

In general, responsibly designed Mac programs should have a menu option for every available command. This is highly discoverable (assuming users know to look in the menus, and the menus aren’t so long or deeply nested that the commands are buried).

Unfortunately in an era of web apps, mobile devices, hacky cross-platform software, etc., fewer and fewer users properly learn the basic Mac platform UI conventions. This particular convention (commands available as menu options with keyboard shortcuts listed next to them) has been largely unchanged for >30 years.

I’m not sure about the precise origin of the shortcut for opening the enclosing folder, but it dates from at least the beginning of OS X.

One Finder shortcut which is less discoverable which you might also find useful is ⌘↓ (command-down) for opening a selected item.