This guide will show you how to install an extension from a local file (such as .zip, .crx, or .xpi) in Safari.
Safari does not support installing browser extensions from arbitrary local files for security reasons.
Extensions must be installed from the Mac App Store or as a signed developer package.
For more information, see Apple's official Safari extension guide.
Tip: Always be careful when installing extensions from outside the official store. Only use files from trusted sources.