(This is a cross-post from the mailing list, reformatted as HTML.)
Since February, I've been working on writing a detailed specification for browser editing, primarily the document.execCommand() and document.queryCommand*() methods. These were created by Microsoft in the 1990s and were subsequently adopted in some form by all other browsers, and today browsers have to implement them to be compatible with web content, but no detailed specification ever existed. Interoperability is practically nonexistent as a result, which has driven all major content editing frameworks away from using execCommand(). (For instance, I began typing this in WordPress' WYSIWYG editor, which uses TinyMCE – a major editor that avoids execCommand() entirely.) Hopefully we can start to fix that and make these APIs a part of the web platform that just works.
The current version of the specification is about fifty pages printed, and supersedes the Editing APIs section of HTML (which is more like two pages). In the style of modern web specs, it is phrased in terms of algorithms that attempt to cover all corner cases unambiguously and leave no behavior undefined, and it tries to match the behavior of existing browsers to the greatest extent possible. At this point, it's stable and complete enough that I believe it's ready for serious review by implementers, and I would like as much detailed feedback as possible.
Anyone reviewing the spec should be advised that I put extensive rationale in HTML comments. If you want to know why the spec says what it does, check the HTML source. I plan to change this to use <details> or such in the near future. There are lots of minor known issues still left, but none that I thought was important enough that it needs to delay review. Feedback can be sent to the whatwg list, CCing me, with [editing] in the subject. (I'm also fine receiving feedback on public-html or public-webapps, but I don't know if the chairs would be okay with that, since it's off-topic.) I should be available to respond to all feedback promptly at least through the end of August. After that, I can't make specific guarantees about my availability, but I do plan to continue maintaining the spec in the long term.