This configuration setting is used to track and find custom board root directories.
When you add a new board and the path to the board root directory is not in the source directory of the application, the SDK, or the west workspace, you must add it to this setting. Entries from this list are then used to populate the Custom list of boards in the Add Build Configuration page.
Tip
The custom board root directory name cannot use empty spaces, as required by Zephyr.