The getLoadedModsInfo command (and the RPT mod table) report CDLC as non-official if the CDLC is loaded using ModLauncherList in Arma3.cfg rather than the -mod list.

Discovered because the 3rd-party Arma 3 Unix launcher uses ModLauncherList rather than -mod, but it's also replicable by using the Expansions menu from within Arma to load CDLC.