Is there a way to use PSPDFKit APIs to inject text into an existing annotation?

Question

Could a Chrome Extension add a script to an existing annotation created by PSPDFKit in order to add a string to an existing annotation instance/bubble?

PSPDFKit APIs are here: https://pspdfkit.com/guides/web/samples/javascript-pdf-annotations/

Example annotation / uploaded doc is here: https://pspdfkit.com/demo/hello

Here's a visual on where the Chrome Extension would ideally place text:

TinyMCE and other advanced editors can be reached (see example below) but this one is more obscure. Any ideas or direction from the Extension gurus?

Example TinyMCE:

var script = document.createElement('script');
script.textContent = "console.log('AP talks to tinyMCE1...'); tinymce.activeEditor.execCommand('mceInsertContent', false, " + JSON.stringify(request.sValue) + ");tinymce.activeEditor.execCommand('mceInsertContent', false, ' - just more.')";
(document.head||document.documentElement).appendChild(script);
script.remove();