The [:]colon character replaces the use of [ _ ] underscore referring to an override.
Check the link for more information https://docs.yoctoproject.org/migration-guides/migration-3.4.html#override-syntax-changes.
The [:]colon character replaces the use of [ _ ] underscore referring to an override.
Check the link for more information https://docs.yoctoproject.org/migration-guides/migration-3.4.html#override-syntax-changes.