MacOS Swap ` (tilde) and § (section) keys in UK Keyboard

README.md

Instructions

1. Copy to ~/Library/LaunchAgents/com.hidutilKeyMapping.plist
2. Open System Settings > Privacy & Security > Input Monitoring and add /usr/bin/hidutil (Hint: Cmd Up will open parent folder and Cmd Shift . will reveal hidden files)
3. Verify hdutil present in System Settings > General > Login Items & Extensions

Verify

1. Preliminary check

plutil -lint ~/Library/LaunchAgents/com.hidutilKeyMapping.plist
# You should see
# /Users/uname/Library/LaunchAgents/com.hidutilKeyMapping.plist: OK

2. Test manually

/usr/bin/hidutil property --set '{"UserKeyMapping":[{"HIDKeyboardModifierMappingSrc":0x700000035,"HIDKeyboardModifierMappingDst":0x700000064},{"HIDKeyboardModifierMappingSrc":0x700000064,"HIDKeyboardModifierMappingDst":0x700000035}]}'

# Allow in System pop-up
# Check if keys swapped

hidutil property --get "UserKeyMapping"
# Should contain
# HIDKeyboardModifierMappingSrc = 0x700000035
# HIDKeyboardModifierMappingDst = 0x700000064

3. Stop/Start using launchctl

launchctl bootout gui/$(id -u)/com.local.KeyRemapping
launchctl bootstrap gui/$(id -u) ~/Library/LaunchAgents/com.hidutilKeyMapping.plist
launchctl print gui/$(id -u)/com.local.KeyRemapping

com.hidutilKeyMapping.plist

<?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>com.local.KeyRemapping</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/bin/hidutil</string>
        <string>property</string>
        <string>--set</string>
        <string>{
            "UserKeyMapping": [
		{ 
          		"HIDKeyboardModifierMappingSrc":0x700000035,
          		"HIDKeyboardModifierMappingDst":0x700000064
		},
          	{
			"HIDKeyboardModifierMappingSrc":0x700000064,
          		"HIDKeyboardModifierMappingDst":0x700000035
        	}
            ]
        }</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
</dict>
</plist>

Tested working on Golden Gate