app/controllers/api/web/embeds_controller.rb

...ascript/mastodon/features/status/components/action_bar.js

app/javascript/mastodon/features/status/index.js

...javascript/mastodon/features/ui/components/embed_modal.js

app/javascript/mastodon/features/ui/components/modal_root.js

app/javascript/mastodon/features/ui/util/async-components.js

app/javascript/packs/public.js

app/javascript/styles/components.scss

app/serializers/oembed_serializer.rb

config/routes.rb