When there is only one job at the top level of the configuration (without any matrix expansion), matrix.include (and its alias jobs.include) completely defines the jobs defined in the build (so the top level job is not included in the build).
When there is only one job at the top level of the configuration (without any matrix expansion), matrix.include (and its alias jobs.include) completely defines the jobs defined in the build (so the top level job is not included in the build).