ARCH_CONSTRUCTOR is used by pxr/base/arch/initConfig.cpp:ARCH_CONSTRUCTOR(Arch_InitConfig, 2, void) pxr/base/tf/initConfig.cpp:ARCH_CONSTRUCTOR(Tf_InitConfig, 2, void) pxr/base/tf/initConfig.cpp:ARCH_CONSTRUCTOR(Tf_InitConfigPost, 202, void) pxr/base/plug/initConfig.cpp:ARCH_CONSTRUCTOR(Plug_InitConfig, 2, void) pxr/base/vt/value.cpp:ARCH_CONSTRUCTOR(Vt_CastRegistryInit, 255)
and by the macros TF_REGISTRY_DEFINE TF_REGISTRY_DEFINE_WITH_TYPE