Currently, builds produced by ceph-build (as shown in Shaman) use the default build flavor.
Since last year’s changes, the default build type is RelWithDebInfo [1].
In some testing scenarios, a Debug build type is useful, mainly to preserve built-in asserts and disable compiler optimizations. See Ceph’s Build Types [2].
Until now, the only way to get a Debug build was to use a branch name suffixed with *-debug.