I added an A/B shortcode generating button to the plain text editor:

The code for the TinyMCE version is also mostly there, though it’s not working and will need some debugging.

Also, as seen in the video, the format of the A/B Shortcode itself has changed, following my discussion last week with Joen. Now instead of the control value being the inline content, it is also a shortcode attribute like the other variants.

All these changes have been committed. Please try it out!