You can look for and install lots of extensions through store page.
Check the extension information on the web page and install, update the extension.
Create your own extension with arvish.
arvish is a collection of tools to make and utilize extensions easier.
Publish extension to npm easily
Publish to store
Check if your extensions is valid easily
Convert alfred workflow to arvis
Change search window's style to your style.
Just click theme button to set predetermined setting values.
Look around what arvis extensions can do for you
Arvis continues to update, fixing bugs and implementing inspiring ideas.
Check change logs on release page to see what's changed.
And Arvis support auto update, so just restart Arvis to update Arvis when you have update.