Like it's already done when you click on an application from a toot, it's opening in a new window.
https://github.com/tootsuite/mastodon/blob/
0254ee9795822ec75ff64ace6ec2b91573bc9a52/app/views/stream_entries/_detailed_status.html.haml#L41
- if application.website.blank?
= application.name
- else
- = link_to application.name, application.website
+ = link_to application.name, application.website, target: '_blank', rel: 'noopener'
%th= application.scopes.map { |scope| t(scope, scope: [:doorkeeper, :scopes]) }.join('<br />').html_safe
%td= l application.created_at
%td