Craig,
They were defined in an old EMR module built as part of the
Mirebalais deploy that was meant to become a core part of the
reference app, but ended up getting phased out in favorite of
moving it's contents into EMR-API + other modules.
https://github.com/PIH/openmrs-module-emr
So, generally, any emr.* message properties should be replaced,
but we haven't done the best job of doing it.
We did copy some of the emr.* message properties into the
uicommons module, so you will find some of them there. However,
we should still try to phase these out.
Take care,
Mark