LDML Keyboard Editor Window
The LDML Keyboard file format is new in Keyman Developer 17. It is an XML file, and follows the specification at https://www.unicode.org/reports/tr35/tr35-keyboards.html
The LDML editor in this release is very basic, supporting syntax highlighting and basic editing, but specific support for the keyboard3 format is scheduled for release in version 18.0.
LDML keyboards can be tested by pressing F5. This opens the LDML Debug window.
The text editor supports standard Windows editing keystrokes. It uses the Monaco component from Visual Studio Code, so much of the functionality available in that editor is also available here.