Rubies themselves cannot parse BBCode: <ruby:[b]aaaa[/b]> will not work because of how DIISIS parses the text content at runtime. However, we can use Godot’s native localization (l10n) system to take care of that.
Step 1: Create rubies with localizable keys.
<ruby:rubies.boldscream>
Step 2: Create a google doc
Download this as a csv file & move it into the godot project files
Step 3: Add it to the project in project settings
Step 4: Wow it works
Why does this work?
This takes advantage of the fact that all Labels and RichTextLabels in Godot will automatically look up their contents on the translation server. if we assume english as the default, we’re just adding an english-english translation (common practice)