Add it to https://searchfox.org/mozilla-central/rev/4654ce1e24a6af17bc96ab60f1f70c218755142f/dom/events/test/browser_navigator_clipboard_readText.js. There should be one "Paste" button for them and the test should dismiss/accept it.
Bug 1777467 Comment 0 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
Add it to https://searchfox.org/mozilla-central/rev/4654ce1e24a6af17bc96ab60f1f70c218755142f/dom/events/test/browser_navigator_clipboard_readText.js. There should be one "Paste" button for them and the test should dismiss/accept it. The scenario in <https://jsfiddle.net/cj50u62m/> may be used.