I am looking at creating a link.
I see no way to select having the link open in a new window.
I can replicate this, it's currently missing. I am not sure it's v1 needed but worth adding later.
Took a stab at what the UI could look like. Happy for feedback!

Picking this up now, based on @jwold's UI
Removing 'needs design' as in progress :) Thanks for tackling this @notnownikki and @jwold 鉂わ笍
If this is going to use an "expandable div" then please see #469. Te toggle should use aria-expanded, the expandable div should be immediately after the toggle in the source order.
I think rather than reopening something that has been added and works, let's create a new issue to enhance and improve it.
https://github.com/WordPress/gutenberg/issues/2667 is the new ticket.
Sorry to reopen, I see a few issues introduced in #2628
1
the "cog" button doesn't have any text or aria-label, it's completely empty so it will be reported by assistive technologies just as "button". Worth noting the other buttons that are very close in the code, they all have an aria-label...
Since it misses an aria-label, the button misses also a tooltip. I'd say it should have an aria-label with text "Link settings" or something along those lines.

2
z-index issue!
see screenshot above: when entering or pasting a link and there are also search results, when pressing the cog button the expanded panel stays below the search results.
To reproduce, insert a link to https://wordpress.org in a couple other posts. Then edit a third post and insert a link pasting in the field https://wordpress.org.
I'd say either increase the x-index or, maybe better, close the search suggestions when the setting panel is expanded, and display them again when the setting panel gets closed.
3
the input field misses a focus style.
This is because the input fields inherit the focus style from forms.css where input of type="url" aren't targeted. Two options here:
type="text" and miss minor advantages given by type="url"forms.css, targeting type="url"4
IE 11 and Edge display a proprietary "X" control in the input fields of type="url":


This would be a minor issue, but unfortunately the spinner that appears when the search runs doesn't look so nice in combination with the "X":

If I remember correctly, a similar issue happened in the Customizer for the menu/widget search field and we just switched back the input field type "search" to "text" (which would also solve the focus style issue).
@afercia thank you! I'll take care of those, perhaps I could ping you for more feedback once I've got them taken care of?
@notnownikki sure! Agreed with @karmatosed to close this in favor of #2667 that should be updated with the right issues (sorry for the confusion).
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Took a stab at what the UI could look like. Happy for feedback!