Most useful xcode shortcut?

The most useful Xcode shortcut mentioned in the "Xcode essentials" session at WWDC 2024 is the "Open Quickly" feature. You can activate it by pressing CMD + Shift + O from anywhere in Xcode. This shortcut allows you to type in part of a file or symbol name and immediately get a list of destinations, making it a fast way to navigate between files. It uses code completion-like matching rules, so you can type any of the unique words in your destination name to get there quickly. If you include a slash in the query, you can match file paths instead of file names, and you can end a query with a colon and the line number to jump to a specific line.

For more details, you can refer to the Xcode essentials (11:22) session.