Comment by philsnow

> I could see a text editor that lets you use a non-healing version of the font for any text that has been written in the viewport and then swaps it out as soon as you no longer looks at that block of text

The text editor widget on their page is a bunch of "line" divs with individual terms being inside spans. If you add an inline style of

  font-feature-settings: "calt" off;

or, more completely,

  font-feature-settings: "calt" off,"dlig" var(--ligatures,1),"ss01" var(--ligatures,1),"ss02" var(--ligatures,1),"ss03" var(--ligatures,1),"ss04" var(--ligatures,1),"ss05" var(--ligatures,1),"ss06" var(--ligatures,1),"ss07" var(--ligatures,1),"ss08" var(--ligatures,1);

to a single line div or a single term span, it won't do the healing. If one of the CSS pseudo selectors worked for these kinds of elements (I see there are a lot that apply to forms, but.. maybe :active / :active-within would work for editable spans?), you could have healing automatically apply to terms when they 'blur' / when they're no longer active.