Tag to be used with the master branch of atlas/athena. Update(s) since 2.0.22: - Updated CheckerGccPlugins; - Update to CLHEP to CLHEP_2_4_0_1_atl02 to fix the bug reported in CLHEP-154; - Updated AtlasCMake/AtlasLCG to use C++17 by default, with all compilers; - Added nlohmann_parser as a new external; - Added VP1LightExternals, with some new external packages; - Updated AtlasLCG to provide find-modules for all the new python modules/externals introduced with LCG_95.