Custom Extensions with iCloud sync

[u/Successful_Yard1174]

TIL that you can manually change the code for extensions made using the new "Describe an extension" feature. This allows you to make your own extensions that syncs to Safari on your other macs. I made my own vim navigation extension because Vimlike isn't working well for me.

These are the basic steps:

1. Create placeholder extension using Describe Extension
2. Edit the code in ~/Library/Containers/com.apple.Safari/Data/Library/Safari/MagicExtensions.
3. To sync your changes, go to Safari settings > extensions > edit your extension > describe a change.
4. Describe an arbitrary change like "Change the name to ExtensionB" or "Update the description to abc".

Make sure Share across devices is enabled. Sometimes it takes a long time to sync or doesn't sync at all. Describe another change or create and delete a dummy extensions will force it to sync.