Change External viewer and lookup in browser settings

The global workaround mentioned by mjpieters no longer works with recent versions of macOS.

Updated workaround:

Create an org.musicbrainz.environment.plist file in ~/Library/LaunchAgents/ with this content:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>org.musicbrainz.environment</string>
  <key>ProgramArguments</key>
  <array>
    <string>sh</string>
    <string>-c</string>
    <string>
    launchctl setenv BROWSER "/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome %action %s"
    </string>

  </array>
  <key>RunAtLoad</key>
  <true/>
</dict>
</plist>

The plist will activate after system reboot. You can also use launchctl load ~/Library/LaunchAgents/org.musicbrainz.environment.plist to launch it immediately. Obviously, you should change the environment variable to the browser of your choice if you’re using something other than Chrome.

See the reference below for caveats.

Reference: