How it's supposed to work:
- Open a page in VisualEditor.
- Select a word. Open the link tool.
- Paste a URL in like this one: https://en.wikipedia.org/wiki/National_Register_of_Historic_Places_listings_in_Concord,_Massachusetts
- Save the magically converted wikilink to that article.
How it's actually working, if the URL contains percent encoding:
- Open a page in VisualEditor.
- Select a word. Open the link tool.
- Paste a URL in like this one: https://en.wikipedia.org/wiki/Wright%27s_Tavern
- See the ugly red error box.
- Manually click on the 'External links' tab.
- Save the page, and see that the URL was converted to a wikilink.