…and it’s not at all bad. Your files have to use the .taskpaper extension to be able to use the built-in functionality, but you get checkboxes (with timestamped date of completion on tick), a drop-down list of projects (from the document title) and drag handles (grey blocks on the right hand side of the screen). You also get tag highlighting, which works surprisingly well when scrolling a long document.
There doesn’t seem to be a tag focus mode (tags are currently non-selectable) and there’s no tag auto-completion, but I’m hoping there’ll be more development along those lines in future updates. That, and other workflows can offer some basic tag navigation. For now, although there’s nothing that I’ve thus far found that offers the plain text folding of FoldingText, Editorial looks like it’s about to become my go-to app for editing FoldingText files.