The field called "Feats" is a one-line textbox.
But a monster/npc can have 10 feats or more. And when we insert "url" bbcode and/or use synthesized feats descriptions, with "return line bbcode" to have a clean view of the feats, the oneline is really not adapted.
Current situation : writing the FEATS in notepad, then, when it is correct, copy/paste it to world anvil's "feats" textbox. When a change must be made, copy/paste the feats textbox to notepad, edit what must be edited, and copy/paste back to world anvil. It's very unconvenient, but technically, it works.
Example on this page, scroll down to the statblock, and search for the "Feats:" in the right column, in the upper block "Statistics" : feats have links and descriptions. (it's in French, but it does not prevent the understanding of this request)
Demand : transform the "feats" oneline textbox in a multi-line textbox, just like the "Skills" textbox for example.
Having a multiline textbox will help a lot to write the feats content by staying in world anvil and not switch to an external editor.
It could be also applied to the fields "Save Modifiers" and "Ability Scores", though it is not as painful as "feats".
Statblocks are made by community members, not the WA team. If there's an issue with one, you'd want to talk to the person who made it to see if the template can be updated.